This is a single-center, single-arm, dose escalation study, to explore the safety, tolerability and efficacy of human amniotic epithelial stem cells (hAESCs) for idiopathic Parkinson's disease (PD).

hAESCs will be administration through the Ommaya reservoir implanted into the lateral ventricle of subjects with idiopathic PD.

This dose escalation will be followed by an exploratory expansion phase in 3 cohorts.

• Dose A (5×10^7 cells/dose)
• Dose B (1.0×10^8 cells/dose)
• Dose C (1.5×10^8 cells/dose).

Inclusion Criteria:

1. 40-70 years old, with more than 5 years of idiopathic PD history
2. UPDRS-III off-time scores ≤49
3. MMSE scores ≥24
4. HAMD-17 scores < 25
5. H-Y on-time scores ≤4
6. reactive to levodopa or dopa agonists
7. PD medication dose is stable for more than 2 months
8. no general anesthesia contraindications, no stereotactic surgery contraindications or other conditions that interfere with clinical evaluation
9. no abnormalities affecting cell transplantation by cranial MRI
10. no participation of other clinical trials 3 months before signing the informed consent

Exclusion Criteria:

1. secondary PD or Parkinson's syndrome
2. subcutaneous apomorphine treatment
3. scoring ≥ 2 on UPDRS-I item 2, or ≥ 2 on UPDRS-II item 13; or ≥ 3 on UPDRS-II item14
4. history of intracranial surgery or device implantation, including deep brain stimulation, within 2 years prior to signing informed consent
5. history of seizures or prophylactic application of antiepileptic drugs
6. other serious central nervous system disorders
7. history of stem cell therapy
8. subject who had undergone a major surgery within 3 months and will undergo a major surgery within the next 6 months prior to signing informed consent
9. autoimmune disease or current use of Immunosuppressants
10. subjects with comorbid cardiac disease, for example, but not limited to, ischemic heart disease, congestive heart failure, significant arrhythmias or cardiac conduction block
11. poorly controlled hypertension, diabetes mellitus, or comorbid endocrine system disorders, pulmonary disorders, gastrointestinal system disorders, serious infections, malignancies, etc.
12. positive for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies, human immunodeficiency virus (HIV) antibodies, or Treponema pallidum antibody
13. abnormalities in liver or kidney function tests, including alanine aminotransferase (ALT), aspartate aminotransferase (AST) is less than 2.5 times the upper limit of normal, blood urea nitrogen (BUN) or creatinine(Cr) are less than 1.5 times the upper limit of normal, or serum albumin < 30.0 g/L
14. abnormalities in hematologic test: coagulation disorders or ongoing anticoagulation therapy; moderate to severe anemia; platelet count < 80 × 10^9/L
15. inability to undergo MRI and positron emission tomography (PET) examinations
16. subject with severe allergies
17. women of childbearing potential (WOCBP) or subject is a man with a WOCBP partner, who are unwilling to take contraception during the trial
18. pregnant or lactating females
19. other conditions deemed by the investigator to be inappropriate for enrollment.