Abstract: Objective: To evaluate the character of a 6 hydroxydopamine induced (6-OHDA) Parkinsonian (PD) rat model.Methods: Unilateral destruction of the dopaminergic neurons of substantia nigra were produced by stereotaxic injections of 6-OHDA in 128 female Sprague Dawley rats. The rats were tested for rotational behavior induced by apomorphine for 40 min every week. The rats demonstrating an average of at least 280 complete contralateral turns/40 min for 4 times in response to apomorphine were selected as PD rats. After 1 month of the lesions the extracelluar liquid were dialysed bilaterally by the intracerebral microdialysis technique. The levels of catecholamines and its metabolite were measured by high performance liquid chromatography analysis. Coronal sections through midbrain of the rat were stained for tyrosine hydroxylase immunohistochemistry. Results: A total 50.5% of the rats rotated over 280 turns per 40 min after 6-OHDA lesions. The PD rats didn't spontaniously occur recovery for 10 months. The levels of dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), seretonin (5-HT), 5-hydroxyindoleacetic acid (5 HIAA) and adrenaline (AD) in lesioned side of the striatium were significantly reduced. TH immunohistchemistry of the midbrain sections revealed a nearly complete absence of TH-immunoreactive cells in the right substantia nigra pars compacta (SNC) and ventral tegmental area (VTA) for the PD rats. There were some TH-immunoreactive cells in the right substantia nigra pars compacta (SNC) and ventral tegmental area (VTA) for the PD rats. There were some TH-immunoreactive cells in the right SNC and VTA of the rats which rotated less 280 contralateral turns.Conclusion: The rats with 6-OHDA destruction of the neurons of substantia nigra may produce a similar neuropathological and biochemical changes to idiopathic Parkinson's disease. This is a stable Parkinsonian rat model.