The Data Release Seven of LAMOST Low-Resolution Spectroscopic Survey (LRS). The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a Chinese national scientific research facility operated by the National Astronomical Observatories, Chinese Academy of Sciences. It is a special reflecting Schmidt telescope with 4000 fibers in a field of view of 20deg^2^ in the sky. Until July 2019, LAMOST has completed its pilot survey, which was launched in October 2011 and ended in June 2012, and the regular survey of the first seven years, which was initiated on September 2012. In this data release, there are totally 10,431,197 low resolution spectra published, which satisfy the selection criteria that the LAMOST LRS General Catalog also used. The data products of this release can be available from the website http://dr7.lamost.org/v2.0/, and they include 1. Spectra. - There are 10,431,197 flux (relatively)- and wavelength-calibrated, sky-subtracted spectra in DR7, including 9,846,793 stellar spectra, 198,272 galaxy spectra, 66,612 quasar spectra, and 319,520 unknown object spectra, and these spectra cover the wavelength range of 3690{AA}-9100{AA} with a resolution of 1800 at the 5500{AA}. 2. Spectroscopic Parameter Catalogs. - In this data release, nine spectroscopic parameter catalogs are also published and they are the LAMOST LRS General Catalog, the LAMOST LRS Stellar Parameter Catalog of A, F, G and K Stars, the LAMOST LRS Line-Index Catalog of A Type Stars, the LAMOST LRS Catalog of gM, dM, and sdM Stars, the LAMOST LRS Multiple Epoch Catalog, the LAMOST LRS Observed Plate Information Catalog, the LAMOST LRS Input Catalog, the LAMOST LRS Catalog of Cataclysmic Variable Stars, and the LAMOST LRS Catalog of White Dwarf Stars respectively. Tens of parameters are included in these catalogs, such as right ascension, declination, signal to noise ratio (S/N), magnitude, gaia_source_id, gaia_g_mean_mag, atmospheric parameters (effective temperature, surface gravity, and metallicity), radial velocity, element abundance, spectral line indices, line widths, the metallicity sensitive parameter, and the magnetic activity flag. Data Release One of LAMOST Medium-Resolution Spectroscopic Survey (MRS). The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a Chinese national scientific research facility operated by the National Astronomical Observatories, Chinese Academy of Sciences. It is a special reflecting Schmidt telescope with 4000 fibers in a field of view of 20 deg^2^ in the sky. Since October 2018, LAMOST started the second stage survey program (LAMOST II), which contains both low- and medium-resolution spectroscopic surveys. LAMOST II takes about 50% nights (dark/gray nights) to continue the previous low-resolution spectroscopic survey, and another 50% nights (bright/gray nights) to conduct the medium-resolution survey (MRS). For LAMOST MRS, it includes two surveys, i.e., the time-domain and the non time-domain surveys. The main purpose of the time-domain survey is to investigate variable targets, which were repeatedly observed in several observation nights, but targets of the non time-domain survey were observed only in one night in general. This time, 11,190,570 single exposure spectra and 2,906,397 coadded spectra were obtained, which were written into 1,498,289 FITS files. For objects close to the moon, spectra may be affected by the moon, thus targets with the angular distances to the moon less than 10 degrees were not observed. For the non time-domain survey, there are totally 988,188 coadded spectra published, and for the time-domain survey, 2,828,655 single exposure spectra were released. The data products of this data release can be available from the website http://dr7.lamost.org/v2.0/, and they include 1. Spectra. - For a target of MRS, we can get two spectra within an exposure, including a blue (B) and a red (R) band spectrum, and their wavelength ranges are [4950{AA}, 5350{AA}] and [6300{AA}, 6800{AA}], respectively. Generally, each object was observed several times, and we would obtain the coadded B and R band spectra by combing the single exposure spectra. Few targets, however, lack of the spectral data of either band for some reason like the wavelength calibration, only one even no coadded spectra exists in their FITS file. For single exposure and coadd spectra, they both have a resolution of 7500 respectively at 5163{AA} (blue) and 6593{AA} (red). 2. Spectroscopic Parameter Catalogs. - In this data release, four spectroscopic parameter catalogs are published, and they are the LAMOST MRS General Catalog, the LAMOST MRS Parameter Catalog, the LAMOST MRS Observed Plate Information Catalog, and the LAMOST MRS Input Catalog, respectively. LAMOST targets were cross-matched with Gaia DR2 catalog, and their Gaia source identifiers and G magnitudes are included in two LAMOST MRS catalogs except the LAMOST MRS Observed Plate Information Catalog and the LAMOST MRS Input Catalog.

Cone search capability for table V/156/dr7lrs (LAMOST LRS General Catalog)

Cone search capability for table V/156/dr7slrs (LAMOST LRS A, F, G and K Star Catalog)

Cone search capability for table V/156/dr7aslrs (LAMOST LRS A Star Catalog)

Cone search capability for table V/156/dr7mslrs (LAMOST LRS M Star Catalog)

Cone search capability for table V/156/dr7melrs (LAMOST LRS Multiple Epoch Catalog)

Cone search capability for table V/156/dr7plrs (LAMOST LRS Observed Plate Information Catalog)

Cone search capability for table V/156/dr7mrs (LAMOST MRS General Catalog)

Cone search capability for table V/156/dr7smrs (LAMOST MRS A Star Catalog)

Cone search capability for table V/156/dr7pmrs (LAMOST MRS Observed Plate Information Catalog)