Long-term excessive application of chemical fertilizers has led to problems such as stunting of citrus trees，reduction of soil organic matter content，soil compaction and acidification，which have seriously affected the sustainable development of the citrus industry in the yellow loam area of the Karst mountains of Guizhou.Using the ‘Aiyuan 38’ citrus orchard as the research object，a field experiment was conducted to study the effects of four kinds of green fertilizers，including peanut (PNT)，red bean (REB)，black bean (BLB)，and soybean (SOB) on soil pH，organic matter and nutrient contents，enzyme activity，and soil composite fertilization of the citrus orchard in the karst mountainous area of Guizhou，using no green manure intercropping as the control，and the correlations between citrus fruit quality indicators and soil environmental factors were analyzed.The results showed that intercropping with green manure treatments improved the soil pH of citrus orchard，effectively alleviated soil acidification，and also improved soil organic matter，alkaline dissolved nitrogen and available potassium content，increased soil enzyme activity，significantly improved the comprehensive soil fertility，and then enhanced fruit quality.Compared with CK，BLB and PNT treatments significantly increased soil pH by 27.64% and 12.88%，respectively.The soil organic matter，effective phosphorus，alkaline dissolved nitrogen and available potassium content in SOB treatment were significantly increased by 22.53%，27.04%，32.02% and 55.87%，respectively.The soil catalase and urease activities in BLB treatment were significantly increased by 39.70% and 121.19%，respectively.Whereas，soil sucrase activity in REB treatment and soil acid phosphatase activity in PNT treatment increased by 50.85% and 56.90%，respectively.The highest edible rate and juice rate of citrus fruits in REB treatment increased by 5.32% and 7.29%，respectively；vitamin C and soluble solids content of citrus fruits in PNT，REB and SOB treatments increased by 9.38%-15.63%，7.07%-12.89%，respectively.The comprehensive soil fertility of each treatment was REB>PNT>BLB>SOB>CK.The results of correlation analysis showed that there was a significant or extremely significant correlation between citrus fruit quality indicators and soil environmental factors，and the formation of citrus quality was directly or indirectly affected by soil environmental factors such as soil pH，organic matter，nutrient content and enzyme activity.The results of redundancy analysis showed that the soil environmental factors affecting the key quality of citrus fruits were soil sucrase activity，available potassium content and catalase activity.In conclusion，green manure could effectively improve the soil fertility level of citrus orchards，promote the supply of soil nutrients，stimulate soil enzyme activity，and then improve the quality of citrus fruits，among which REB (red bean) had the best effect and could be prioritized as a green manure variety for citrus orchards in the yellow loam area of the Karst mountains in Guizhou.