Abstract: In this paper, it is reported that the results of determining esterase isozymes of 12 various tissues or organs of embryo, germinate, leaves, stamen ctc. from 50 hybrid rice and their parents by means of polyacrylamide gel electrophoresis. According to our experiment, the zymograms of csterase isozymes of hybrid rice can be divided into 5 types: complementary, patroclinal, matroclinal, homotypic and "hybrid" zymograms. In stronger hybrid vigor combination, there are more complementary zymogram and less patroclinal, matroclinal and homotypic zymograms. In weaker hybrid vigor combination, there are only homotypic zymogram. "Hybrid" zymogram only cxists in leaves at three-leaf stage of both Shan You 63 and Wei You 63 and leaves at differentiation stage of young panicle of Wei You 64.