The intrinsic energy distribution for 41 spectral subclasses in the range of wavelengths of 320-760 nm are derived in the following way: (1) The sources of the spectrophotometric data were taken from three catalogues published in FSU (Kharitonov et al. 1988, Glushneva, ed., 1982, Alekseeva et al. 1992), containing energy distributions of about 2000 stars of different spectral types. (2) MK spectral classes were taken from the Bright Star Catalogue (Hoffleit 1982; hereafter BSC). The paper by Gray and Garrison (1987) was took into account to examine the influence of errors in spectral classification. (3) The quality of stars selected for each subclass was estimated by comparison of the observed and synthetic (U-B) and (B-V) color indices calculated for our energy distributions. The results have been published by Knyazeva and Kharitonov (1993, 1994a, 1994b, 1996a, 1996b)