Abstract: Process of peanut embryonic development,including zygotic development 3-6 days after fertilization was observed with plastic thin section microscopy and scanning electron microscopy in this study.The observed results showed that anther sacs of peanut bursted before the flower opened at 3-4 o' clock in the early morning,and possibly self-pollinated.About 20-21 hours after anther bunted,the egg cell was fertilized.Before peg penetrated into the soil,the development of zygote was rather slowly,however,the zygote developed into proembryo and grew up quickly after the peg entered the soil.Proembryo began differentiating about 15 days after an thesis,and the differentiation of embryo completed in 25-30 days later,in which 5-6 young leaves and the first inflorecence primordium were observed.Also,the development of apex seed was about one young leaf slower than that of base seed.