【Objective】The effects of long-term and different proportions of organic fertilizer on the content of labile/non-labile carbon components and the stability of the chemical structure of organic carbon in paddy soil were determined.【Method】This study selected a long-term positioning test of paddy soil developed by Quaternary red clay as the research object. Five treatments were selected: no fertilizer treatment (CK), chemical fertilizer treatment (100F0M), 30%, 50% and 70% of the nitrogen in chemical fertilizer treatment was replaced by organic fertilizer (70F30M、50F50M、30F70M). During the study, we measured the content of total organic carbon, labile/non-labile organic carbon pool, the chemical structure of organic carbon, and soil properties.【Result】 The contents of organic carbon, labile carbon and non-labile carbon in paddy soil were increased by different proportions of organic fertilizer instead of chemical fertilizer. The contents of labile carbon were 70F30M, 30F70M > CK, 50F50M, and the contents of non-labile carbon were 30F70M > 70F30M, 50F50M > 100F0M > CK. With an increase in the replacement proportion of organic fertilizer, the proportion of non-labile carbon gradually increased from 69.67% to 77.26%. Under different organic fertilizer substitution ratios, the chemical structure of soil organic carbon remained the same, and the relative content percentage shows the same trend: aromatic carbon (33.28% ~ 37.79%), alkyl carbon (27.81% ~ 31.19%), alkoxy carbon (16.19% ~ 20.10%), carbonyl carbon (10.35% ~ 12.07%), and carboxyl carbon (2.52%~ 5.75%).Alky, carbonyl, and carboxyl carbons made up the largest, second largest and lowest proportions, respectively.With the increase in the proportion of organic fertilizer instead of chemical fertilizer, the aromaticity increased from 0.40 to 0.44 while the ratios of aliphatic carbon/aromatic carbon and alkyl carbon/alkoxy carbon decreased, suggesting an increase in the stability of organic carbon. PH (P< 0.05) and Cation exchange capacity (CEC, P< 0.01) were the main influencing factors of activated carbon content. pH, CEC, Alkali hydrolyzed nitrogen (AN) and carbon input(organic fertilizer, rice root and rice stubble) (P< 0.01) were the main influencing factors of non-labile carbon content.【Conclusion】30F70M not only improved the content of labile and non-labile carbon but also increased the aromaticity of organic carbon, which is more conducive to improve the stability of soil organic carbon.