This paper studies the variation of the characteristics of current transport processes with the grain size in amorphous and polycrystalline silicon films prepared by both CVD and GD methods. The tailing width of the films deposited in a range around the crystallization temperature decreases obviously with the increasing grain size and it tendsto disappear if the grain size increases to about 700-800A. The transport processes of the films （with crystalloid less than 200A）deposited below the crystallization temperature exhibit mainly the amorphous characteristics

and the Mott-Davis localized conducting model is also usable. The low temperature transport process in the films deposited above the crystallization temperature are attributable to the deep trapped levels arising from the polycrystalline grain boundaries