Abstract: 【Objective】 To analyze effects of fertilizer reduction on leaf photosynthetic characteristics, yield and quality of greenhouse tomatoes. 【Method】 Four treatments were set up in the experiment: conventional fertilization (the CK, chemical fertilizer reduction by 15% (OPT-15), chemical fertilizer reduction by 30% (OPT-30) and fertilizer reduction by 45% (OPT-45) to measure relative indexes of growth, physiology, yield and quality of tomatoes. 【Result】 Results showed that compared with CK, reduction of fertilizer by 15% promoted the growth of the plant height and stem diameter, increased weight of average tomato fruit and yield, increased the sugar and acid ratio of fruit but the thickness of leaves, the content of total sugar and VC in fruit were decreased. Reduction of fertilizer by 30% promoted the growth of the plant stem diameter, and enhanced the photosynthetic rate of tomato leaves, increased leaf thickness, improved the weight of average tomato fruit and production, increased the total sugar, VC content in fruit and sugar acid ratio, all in all, the effect of increasing production and improving quality was better. Reduction of fertilizer by 45% reduced the growth of plant height and stem diameter, reduced the blade thickness, decreased the sugar acid ratio, but increased the leaf photosynthetic rate, single fruit weight and yield and increased total sugar and VC content in fruit. 【Conclusion】 Thus,it can be seen that reduction of chemical fertilizer by 30% can not only reduce the input of fertilizer, but also improve the yield and fruit quality of tomato.