In order to study the application of glial cell line-derived neurotrophic factor (GDNF) in clinic, gene mutation, fusion protein expression in E.coli and purification methods have been used to obtain the fragments of GDNF, GDNF(ΔN39), GDNF(ΔN39)-R9. Using primary cultured dopaminergic neurons and PC12 cells with transfected with GFRα1 and Ret to observe their biological function and cytotoxicity. Using B-Endo3 cells and Transwell method to analyze their delivery across the cellular membrane and blood brain barrier. The results show that GDNF(ΔN39)-R9 has the same neurotrophic function with wild GDNF and nearly no cytotoxicity to dopaminergic neurons and PC12-GFRα1-Ret cells and can get through effectually the cellular membrane and simulacrum of blood brain barrier with matrigel and B-Endo3.