Abstract: In order to investigate the effects and mechanisms of the Combined Anaesthetic for Miniature Pigs(CAMP) on the hemodynamics in miniature pigs, fourteen Chinese laboratory miniature pigs were injected with the CAMP (0.15 mL·kg1). Precaval vein blood was collected at 0, 5, 10, 30, 45, 60, 80, 100 and 120 min before and after administration, and noninvasive blood pressure（NIBP）and heart rhythm（HR）were monitored at the same time. Plasma renin activity（PRA），angiotensin Ⅱ（AⅡ）and aldosterone（ALD）were determined by radioimmunoassay. Results showed that NIBP and HR were significantly changed at 5—10 min and 80 min（P<0.01 or P<0.05）. Changes of PRA, AⅡand ALD were similar to that of SBP, DBP, MAP and HR, and correlation among them was found, especially in SBP, DBP and MAP. It was concluded that PRA, AⅡand ALD participated in changing of hemodynamics caused by the CAMP, and ReninAngiotensinAldosteroneSystem might be one of the main factors to change hemodynamics.