The effects of co-application of organic and chemical fertilizers on nutrient uptake and soil fertility of citrus trees were studied through field experiment.Results showed that the yields of citrus were increased by the treatments of 25% or 30% of chemical fertilizers substituted with organic fertilizers，and the highest increment rate was 9.8%.The treatments of chemical fertilizers partly substituted with organic fertilizers could meet the demand of nitrogen，phosphorus and potassium，and could also increase the absorption of medium and trace elements in citrus.The soil pH and organic matter were all significantly increased by the two treatments of chemical fertilizers partly substituted with organic fertilizers，and the average increment rate were 7.7% and 12.4%，respectively.In addition，chemical fertilizers partly substituted with organic fertilizers significantly increased the activities of urease，acid phosphatase，catalase，sucrase，cellulase and dehydrogenase in soil. The combination of organic and chemical fertilizers for two consecutive years not only reduced 30% of chemical fertilizers application，but also improved citrus yield and soil fertility.Overall，the treatment of 30% chemical fertilizer substituted with organic fertilizer is the best.