A Study To Evaluate the Safety and Efficacy of Human Neural Stem Cells for Parkinson's Disease Patient

Inclusion Criteria: * Patient diagnosed with idiopathic PD, at least with two key symptoms (Static tremor, bradykinesia, rigidity ) , without any other evidence of Secondary Parkinson's syndrome. * Disease course ≥7 years，modified Hoehn-Yahr is 3-5 stage * Patient age ≥35 years * Patients receiving a stable dose of levodopa for at least 1 months with the expectation that the treatment will remain unchanged throughout the course of the study * The doses of levodopa ≥300mg •Signed informed consent form (ICF) by patient self or his law-in relationship before enrollment. Exclusion Criteria: * Hepatic dysfunction(transaminase ≥1.5 normal range), Renal dysfunction(Cr\>2.0mg/dl or 177μmol/L)，Cardiac dysfunction or other severe systematic diseases etc. * Suffering malignancy or during anti-cancer treatment period. * Pregancy, lactation or possible pregancy and plan to pregancy patient * Attended other intervention clinical trial within 3 months aftre getting ICF, or during other ongoing intervention clinical trial * Investigator think inappropriate patient for this protocol