Based on the field experiment，the effects of combining compost with chemical fertilizers on the content of soil humic substances carbon fractions and main nutrients were investigated，aiming to clarify the fertilizing effect of green plant waste compost on soil and provide a scientific basis for improving fertilization strategies and enhancing soil quality. Six treatments were set up:no fertilization，100% chemical fertilizer，25% compost+75% chemical fertilizer，50% compost+50% chemical fertilizer，75% compost+25% chemical fertilizer，and 100% compost. Soil total organic carbon，humic substance carbon fractions，and basic chemical properties were measured after 150 and 500 days of fertilization. The results indicated that combining compost with chemical fertilizer effectively increased the ratios of humic acid to fulvic acid and humic acid to humin，decreased the carbon to nitrogen ratio，and enhanced the degree of humification. In the short term，applying chemical fertilizer alone did not significantly affect the accumulation of soil humic substance carbon fractions. Compared to applying chemical fertilizer alone，combining compost with chemical fertilizer increased the content of total organic carbon，water-soluble organic carbon，humic acid carbon，fulvic acid carbon，and humin carbon in soil by 1%-14%，10%-24%，5%-29%，3%-16%，and 1%-19%，respectively. Under equal nitrogen fertilization conditions，combining compost with chemical fertilizer effectively enhanced soil available nutrients and reduced soil pH after 150 and 500 days. This combination increased the content of alkali-hydrolyzable nitrogen，available phosphorus，and available potassium in soil by 3%-48%，1%-15%，and 9%-22%，respectively，with the 50% compost + 50% chemical fertilizer treatment showing the best effect on nutrient enhancement. These results suggested that combining compost with chemical fertilizer effectively increased the quantity of soil organic carbon and significantly impacted soil humic substance carbon fractions. The 50% compost + 50% chemical fertilizer treatment not only promoted the formation of soil humus but also facilitated the enhancement of main nutrients，making it a recommended fertilization method.