Pot experiment was carried out in greenhouse to explore the effect of negative pressure water supply on soil nutrients and soil bioactivities of Capsicum annuum L.using the negative pressure water supply device by means of continuous negative pressure water supply.4 treatments,namely,-5,-10,-15 kPa and manual irrigation(CK)were set up in the experiment,so as to determine soil alkalihydrolyzable nitrogen,available phosphorus and available potassium contents,as well as soil catalase,urease,sucrase and phosphatase activities at all growth stages of Capsicum annuum L..The results indicated that soil alkalihydrolyzable nitrogen,available phosphorus and available potassium contents,as well as 4 soil enzyme activities at all growth stages of Capsicum annuum L.were remarkably higher than those in CK when the water supply pressure was controlled at -5 kPa to -15 kPa.Among them,-5 kPa treatment significantly increased soil nutrients and enzyme activities.Correlation analyses of soil available nutrient contents and enzyme activities indicated that,under negative pressure water supply conditions,soil enzymes showed distinctly positive correlation with soil available nutrients among the 4 soil enzymes,among soil alkalihydrolyzable nitrogen,available phosphorus and available potassium,and among soil enzymes and soil nutrients.Principal component analysis revealed that the first principal component had great contribution to the comprehensive soil fertility level.In addition,the second principal component suggested that available phosphorus and available potassium decreased as catalase and sucrase decomposed and decreased.In conclusion,adopting the negative pressure water supply manner can promote soil enzyme activities of Capsicum annuum L.,which is beneficial to the transition of soil nutrients of Capsicum annuum L..Furthermore,the effect on improving soil fertility of Capsicum annuum L.is more outstanding when the water supply pressure is stable at -5 kPa.