The rat model with a unilateral 6-OHDA-induced lesion of the dopaminergic system was used for experimental study on gene therapy for Parkinson's disease (PD). The plasmid pCMVTH (6.04 kb) was constructed as a vector containing the gene of tyrosine hydroxylase (TH) and transferred into cultured primary muscle cells by lipofection ex vivo. After expression of TH was determined in vitro, the intracerebral grafting (ICG) of these genetically modified cells was made in the striatum of PD rat model. The results showed that TH-expressing muscle cells had a long-term survival in the brain and induced a marked decrease in abnormal locomotion and increase in striatal dopamine levels for rat model.