This paper used SEM to observe the flower organ ontogeny process, in order to know the flower base number of Phytolacca and whether or not its stamen and pistil derived from leave, than to clarify the model of Phytolacca flower ontogeny. The results show that: (1) after flower primordia initiated, two bractlets of two species initiated one by one. Than the perianths initiated one by one, the bractlets and perianths initiated can be clockwise or counterclockwise, and they are with the same direction. They all initiated by 2/5 circumference spiral. (2) When the perianths had initiated over, the stamens initiated on ring meristem of flower top meristem, and the stamens ontogeny almost at same time, and there is no any order; and while the flower has two rounds of stamen, the inner round first initiate, in some time, the out stamen alternate with perianths, out round stamens also did not opposite to perianths. (3) Carpels of two species initiate alternate with stamen (or inner stamen), and carpel initiates almost at same time, no order. Phytolacca flower is 5 base number flower, but the stamen and carpel were not fit with 5 base number, because they all initiated on ring meristem. (4) The flower of Phytolacca ontogeny is no any relation with 3 base number flower. When stamens are multiround, the out round initiate lately. At the end, the flower of Phytolacca is 5 base number, and the results did not support the flower of Phytolacca is 3 base number ontogeny model.