Fluvo-aquic soil is the main cultivated soil in the North China Plain. However, due to the sandy texture of the impact plain and the long-term unreasonable utilization, the soil structure is poor, the organic matter content is low, the nutrient is unbalanced, the plough layer is shallow, and the water and nutrient use efficiency is low, which restricts the further improvement of crop productivity and the sustainable development of agriculture. In order to explore the degradation process of corn straw and the change rule of organic carbon groups in straw and its influence on organic matter and humic acid in fluvo-aquic soil, this paper set the ratio of soil to straw as 50 : 1 + 30 kg / mu nitrogen fertilizer ( HN ) for fluvo-aquic soil in North China Plain. The ratio of soil to straw was 50 : 1 + no nitrogen fertilizer ( H ) ; the ratio of soil to straw was 200 : 1 + 30 kg / mu nitrogen fertilizer ( LN ) ; four treatments with a soil to straw ratio of 200 : 1 + no nitrogen fertilizer ( L ). The results showed that : ( 1 ) The degradation amount of corn straw increased with the increase of culture time. On the 180 th day of culture, the degradation rate of corn straw treated with H was the highest, reaching 77.33 %. ( 2 ) In the process of straw degradation, the relative content of carbonyl carbon, aromatic carbon and alkyl carbon increased, and the relative content of alkoxy carbon decreased. ( 3 ) The content of organic matter in fluvo-aquic soil increased with the increase of straw amount and incubation time. Under the same nitrogen application level, compared with the low amount of straw returning treatment, the organic matter content of no nitrogen fertilizer and nitrogen fertilizer treatment increased by 13.88 % and 12.19 %, respectively. The absolute content of HE in fluvo-aquic soil was related to the application amount of straw. Compared with the original soil sample humic acid content, HN and H treatments increased by 3.33 % and 5.58 %, respectively, while LN and L treatments decreased by 12.32 % and 13.79 %.