Our muSR study on Ce(Os1-xFex)2Al10 with x=0.4, which reveals long range magnetic ordering below 24K from the heat capacity, shows unexpected temperature dependence. The muSR spectra only show frequency oscillations below 5K, in agreement with the neutron diffraction study at 2K. However, between 5 to 17K muSR spectra exhibit Lorentzian Kubo Toyabe (KT) times exponential (EXP) decay behaviour and above 30K the spectra exhibit Gaussian-KT times EXP-decay behaviour. In our preliminary diffraction study on D20 we have seen three clear magnetic Bragg peaks at 2K. There is also an evidence of very broad peak near 32.7 Å in 2 K compared to 30K data, however this range is close to the limit of D20 and hence we need WISH to investigate a detail temperature dependence of the magnetic structure. Further 32.7 Å peak was also seen in CeRu2Al10 below 5 K on WISH and need further investigations.