Silicon thin films material with different crystalline ratio (Xc) have been deposited with varying silane content of source gases in the PECVD process. We have researched how hydrogen content affects the material and the relationship between micro-structure and optoelectronic properties. Light soaking experiment was then performed. By comparing the changes in the properties before and after irradiation, we conclude that the amorphous region is responsible to the degradation of the photoelectronic property. The mixed phase amorphous silicon degrades less and is more stable than component the common amorphous silicon. The highly crystallized silicon is stable against light soaking. The microcrystalline silicon near the threshold is not so stable as the highly crystallized one, but its optoelectronic property is more suitable than the others for making microcrystalline silicon solar cells.