The effects of differents deposition conditions including the reaction gas pressure, the RF power and the hydrogen dilution ratio of silane on the characteristics of un-doped amophous silicon have been studied in this paper. The light-induced changes of the relative materials have also been analyzed. The IR absorption spectrum, the photo and dark conductivity, the sub-band-gap absorption spectrum and the secondary ion spectrum for the materials have been measured as well.The results show that the stability of amorphous silicon solar cell has the direct relationship to the content of Si:Hx(x=2.3), besides to the defecfs such as weak bond and microviod, etc.