Parkinson’s disease is a common chronic neurodegenerative disease.N-methylation can enhance the neurotoxiicity to dopaminergic neuron in the metabolic process of catechol isoquinolines and Salsolinol N-methyltransferases (SNMT) may play an important role in the pathogenesis of PD.A new method including SNMT purification and detecting SNMT activity was developed and displays an excellent sensitivity and stability.In addition,the SNMT activity in Wistar rats substantia nigra,striatum and cerebellum.