A novel polymer- overoxidized polypyrrole film chemically modified electrode (CME) as the liquid chromatography-electrochemical detector (LC-ECD) was fabricated and applicated, which could be used to determine the monoamine neurotransmitters. The experimental model of parkinsonian animal was established by using medicine. Microdialysis sampling coupled with LC-ECD was used to monitor the monoamine neurotransmitters and their metabolites in experimental animal brain in vivo under different situations. The mechanism of experimental animal's Parkinsonian disease was studied elementarily. An accurate and reliable analysis method was supplied for filting the new and the more effective medicine to cure parkinsonian disease.