Crossbreeding between Epinephelus coioides( ♀) and Epinephelus lanceolatus(♂) was conducted by artificial insemination. Fertilized eggs were collected at 0,30,90 s,2,3,4,5,6,7,8,9,10,11,12,13,14,15 min post-insemination respectively,which were fixed by Smith’s solution,embedded by paraffins and stained by H. E. According to the characteristics of Epinephelus coioides eggs,tissue section method was modified. The results showed that the sperms of Epinephelus lanceolatus rapidly entered the eggs of Epinephelus coioides at 30 s- 1min post-insemination. Observation results of tissue sections showed that mature eggs of Epinephelus coioides remained at metaphase of secondary maturation division. The eggs were activated after sperm penetration into the egg. With the development of secondary maturation division,at 2 min post-insemination,eggs reached the metaphase of secondary maturation division; at 3- 6 min post-insemination,sperm asters appeared; at 5 min post-insemination,eggs extruded secondary polar body; at 7- 15 min post-insemination,male pronucleus and female pronucleus moved closer to each other and fused finally,forming a clear junction line; subsequently,zygote nucleus formed and karyotheca became faint; at 15 min post-insemination,first karyokinetic division was developed. Crossbreeding between Epinephelus coioides (♀) and Epinephelus lanceolatus (♂) was conducted by artificial insemination. Fertilized eggs were collected at 0,30,90 s, 2,3,4,5,6,7,8,9,10,11 , 12,13,14,15 min post-insection respectively, which were fixed by Smith’s solution, embedded by paraffins and stained by HE According to the characteristics of Epinephelus coioides eggs, tissue section method was modified. The results showed that the sperms of Epinephelus lanceolatus rapidly entered the eggs of Epinephelus coioides at 30 s- 1 min post-insemination. Observation results of tissue sections showed that mature eggs of Epinephelus coioides remained at metaphase of secondary maturation division. The eggs were activated after sperm penetration into the egg. With the development of secondary maturation division, at 2 min post-insemination, eggs reached the metaphase of secondary maturation division; at 3- 6 min post-insemination, sperm asters appeared; at 5 min post-insemination, secondary polar body; at 7- 15 min post-insemination, male pronucleus and female pronucleus moved closer to each other and fused finally, forming a clear junction line; subsequently, zygote nucleus formed and karyotheca became faint; at 15 min post-insemination, first karyokinetic division was developed.