Objective To observe the effects of intranigral injection of lipopolysaccharide (LPS) on the motor behavior and dopaminergic neurons (DA) in the brain of rhesus mI>onkey/I>, in order to explore the mechanism of inflammation in the progressive degeneration of the dopaminergic neurons. Methods Five adult rhesus mI>onkey/I>s（Macaca, M1-M5, 4 males and 1female）were taken for the experiments. Among them 4 mI>onkey/I>s were intranigrally injected with LPS and survived 24 weeks (M1and M2) and 48 weeks (M3 and M4) respectively after the operation. One mI>onkey/I> (M5) was only injected with saline as a control animal. The injections (LPS or saline) were stereotaxically made 3 times (at weeks 0, 8, 16 respectively; 40μl for each) in the substantia nigra on one side. Moving distance and speed were measured by Ethovison software . The movement time of upper limbs was recorded by using a MI>onkey/I> Automated Movement Assessment Panel. The number of tyrosine hydroxylase (TH)positive neurons and microglia in the substantia nigra was demonstrated by immunohistochemistry staining. Results 1.The tests of locomotion distance and speed in the mI>onkey/I>s decreased apparently after the injection of LPS (24 and 48 weeks) as compared with that in the control animal. 2.The movement time of the upper limb opposed to the injection side decreased also apparently: For M1 and M2, the arm movements were prolonged by 36.1% and 27.1%; the hand movements were prolonged by 41.2% and 28.6%; for M3 and M4, the arm movements were prolonged by 76.5%(P<0.01) and 50%(P<0.01), and the hand movements were prolonged by 81.8%(P<0.01) and 55.6%(P<0.01). No changes could be seen in the limbs, ipsilateral to the injection, neither in the control case, M5. 3.The number of TH-positive neurons in the injected substantia nigra decreased to some degrees, which was more obvious in the cases of M3 and M4. 4.The microglia were activated in the area in all LPSinjected cases especially in the cases of M1 and M2. Conclusion The injection of LPS can induce brain inflammation which leads to a long-term an