| In this study, in order to do research on the progress of Hyriopsis cumingii embryos and explore the in vitro culture its early embryos, male and female gametes obtained by anatomy were used as materials for in vitro fertilization and in vitro culture with isoosmotic balance salt solution (BSS) suitable for freshwater mussels. And the morphological characteristics of each stage of embryo were observed with the required time for development recorded. Meanwhile, the embryos in its nurturing pouch of outer gill were continuously observed and calculate the embryonic developmental biological zero point and effective accumulated temperature of embryonic development at the same time. Results show that when the water temperature is 25 ± 1 ℃, the anatomy of the sperms and eggs were mixed after diluting by BSS saline and observed fertilized eggs with polar body emissions at 1.8 h, 2-cell stage at 2.8 h, 4-cell stage at 5.6 h, 8-cell stage at 10.5 h, 16-cell stage at 13.9 h, and morula stage at 17.3 h under optical microscope. And then embryos did not change, and some of embryos were deformed. Meanwhile, when the average water temperature in the pond was 26.54 ℃, 28.08 ℃ and 29.51 ℃, it took respectively 10, 9 and 8 d for embryos to develop into mature glochidium. And the biological zero point for embryonic development of H. cumingii was 14.81℃, and the effective accumulated temperature were 12.95 ℃×d, 25.99 ℃×d, 42.27 ℃×d, 69.21 ℃×d and 118.14 ℃×d for embryos developing to cleavage stage, blastocyst stage, gastrulation stage, glochidium stage, mature mlochidium stage, respectively. The results of this study can provide reference for the researches on artificial breeding and development of modern biological genetic breeding technology of H. cumingii.