Abstract: The effects of microinjecting rotenone into SNc on the behavior and spontaneous activities of the ventrolateral thalamus neurons in rats were studied. 28 days after the injection of rotenone, both the latency of rats′ moving on verticalgrid and the numbers of rats′ sliding down the declinedplane significantly increased. The willful movements of animals were significantly decreased, and the time of inactive sitting was significantly increased. The spontaneous discharge rate of the VL neurons significantly decreased. Neurons with type〖KG-*4〗Ⅰbursting fire decreased, however, the regular fire and type〖KG-*4〗Ⅱ bursting fire increased. The peaks of the power spectrum of neurons moved to the low frequency area. The results suggest that microinjecting rotenone into SNc could cause symptoms similar to Parkinsonism syndrome such as rigidity, slow moving, and tremor etc. The results also indicate that it also causes the decrease of spontaneous electroactivities of VL neurons and the changes of their firing patterns.