Abstract: The comparison of photsynthetic functions among hybrid rice and their parents has been studied. The experimental results show that the chlorophyll and cartenoid contents per unit fresh weigh of leaf in hybrid rice are higher than those in their parents. The potential activity and the efficiency of primary conversion of light energy of PSⅡ , the efficiency of potential photosynthetic quantum conversion of a leaf, the photosynthetic electron transport rate and the regulation capability of excitation energy distribution between PSⅡ and PSⅠ induced by Mg2+ in hybrid rice are higher than those in their parents from the hybrid combinations possessing heterosis. In addition, the above mentioned photosynthetic functions of their female parents are better than those of their male parents, respectively. Howoever, these functions of male parent are better than those of female parent and their hybrid rice in non-heterosis hybrid combination. The experimental results futher suggest that the female parents possessing excellent photosynthetic functions should be chosen when hybrid combinations are made. It is an important way to obtain good hybrid rice to be popularized and applied in rice production.