BACKGROUND:: Currently, there are plenty of the investigations regarding the induced differentiation of neural stem cells (NSCs) in vitro, but the process of differentiation is difficult to control, many methods are complicated to operate, and the proportions of differentiation are very low. OBJECTIVE:: To discuss in vitro cultivation of rat embryonic forebrain NSCs and to observe the differentiation rule of NSCs. METHODS:: The forebrains were isolated from fetal rats under aseptic conditions, to prepare monocell suspension, and cultured with DMEM/F12 medium containing N2 at the density of 1×10/L. In the process of cultivating, BrdU was added to mark NSC spheres. The induced differentiation experiment was divided into three groups: polylysine culture plate, gelatin plate and no plate culture groups. 20% volume fraction of embryonic bovine serum was used to stimulate the differentiation. Immunohistochemistry method was applied to detect the level of nestin and BrdU, as well as NSCs differentiation into nerve cells in the serum induction. RESULTS AND CONCLUSION:: The cells presented the NSC-like growth and continuous proliferative capacity, they can subculture. Nestin and BrdU were both positive in passaged neurospheres. The inducing differentiation effect of the polylysine culture plate group and the gelatin plate group was greater than no plate culture group (P < 0.01), and the polylysine culture plate group had a little higher percentage of neurons differentiating than the gelatin plate group (P > 0.05). The result of immunohistochemistry was glial fibrillary acidic protein-positive and microtubule-associated protein-2-positive. Rat embryonic forebrain is full of NSCs. The polylysine and the gelatin as cells holder in inducing NSCs differentiation can improve NSCs differentiation and mostly differentiate into the astrocytes through differentiation observation.Sun L, Zhang L, Hu XF, Zhang H, Luo Q, Wang XS, Zhu DX, Bo AH.Effect of polylysine and gelatin on proliferation and differentiation of neural stem cells. Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu. 2010;14(47): 8755–8758.[http://www.crter.cn http://en.zglckf.com]