Objective To analyze the etiology and pathogenesis of HIV/AIDS patients in XiShuangBanNa for providing a theoretical basis for clinical research and treatment. Methods Epidemiological investigation and comparative analysis methods were used in this topic to survey the current situation of HIV/AIDS patients and patients in the control group. Meanwhile， to explore and summary the etiology and pathogenesis of HIV/AIDS patients by analyzing the clinical symptoms， syndrome factor， tongue and pulse comparatively. Results Compared to the control group， the frequency of clinical symptoms of the case group are higher than those in the control group. the main differences of clinical symptoms are itchy skin， look dim-complexioned， aversion to cold and cold extremities， aversion to wind and cold， numbness of the limbs， a pale lip and nails， easy to catch a cold. Compared to control group， the frequency of syndrome factor in the case group as Blood stasis， dampness， spleen qi deficiency， blood deficiency， Jing deficiency and kidney are higher except the syndrome factor heat is lower. And pink tongue with yellow and greasy coating or thin and white coating， normal tongue shape， or fat-large with tooth mark and wiry and slippery pulse were the main symptoms in HIV/AIDS group. Conclusion For the HIV/AIDS patients in XiShuangBanNa， the causal relation between etiology and dampness pestilence is inseparable based on the currently existing sample size and study methods. qi deficiency and blood deficiency were showing after the dampness pestilence violate the human body， the main involved visceras are spleen and kidney and then causing the qi， blood， yin and yang deficiency and formated the deficiency in origin and excess in superficiality， causing the deficiency-excess complication pathological changes.