The effect of the combined application of controlled release nitrogen fertilizer and water-soluble fertilizer on the physiological characteristics and quality of tomatoes was explored to provide a reference for reasonable nitrogen fertilizermanagement in the tomato planting process in greenhouse.Pot experiment was used to study the changes of tomatoyield，quality and physiological characteristics.There were 5 treatments in the experiment:no nitrogen control(CK)，conventional fertilization(urea+water soluble fertilizer，U100)，conventional nitrogen reduction 20%(urea+watersoluble fertilizer，U80)，controlled -release fertilizer(controlled -release nitrogen+water soluble fertilizer，PCU100)and controlled-release fertilizer nitrogen reduction20%(controlled -release nitrogen+water soluble fertilizer，PCU80).Theresults showed that compared withCK，nitrogen fertilizer application significantly increased tomatoyield，but there was nosignificant difference within N applicationtreatments；compared withurea，controlled release fertilizer significantly reducednitrate content of tomato，net photosynthetic rate and nitrate reductase activity( P<0.05).Compared with urea，theactivities of glutamine synthetase and glutamic acid synthetase were not significantly affected by controlled releasefertilizer.In conclusion，the combination of controlled release nitrogen fertilizer and water -soluble fertilizer could improve the netphotosyntheticrate，nitrate reductase activity and quality oftomato.The combination of controlled -release nitrogen fertilizer and water-soluble fertilizer affects the physiological characteristics of tomato by regulatingchlorophyll，photosynthesis andnitrogenmetabolism，and then affects the yield and quality.