Abstract: The results of colony photosynthesis indicators experiment of different silage maize showed that Leaf Areas Index (LAI), Leaf Areas Duration (LAD) and Colony growth rate of different silage maize presented single-peaked curves during growth stages, and the peak was in pollen-scattering stage and milk stage, the net assimilation rate of different silage maize presented saddle curve. Keshi No.1, which has stronger tillering ability, and Donglingbai and Nongda 647, which have higher plant height, showed higher LAI and LAD. Colony growth rate of Donglingbai was higher than other silage maize in earlier and middle growth stages, significantly, and it was the most important physiological foundation for higher biomass. The colony biomass of silage maize with higher plant height could be improved in condition of control diseases and logging through applying integrated cultivation measures.