Abstract: Based on the analysis of the effects of tillage measures and straw returning on soil aggregate and soil carbon and nitrogen storage in maize field, the relationship between soil aggregate carbon and nitrogen content and soil carbon and nitrogen storage was analyzed, aiming to provide theoretical basis for the research and development of soil carbon and nitrogen retention technology in farmland in arid oasis irrigation area. Field experiments were conducted from 2015 to 2018, and four treatments were set up: traditional tillage + no-straw returning (T), traditional tillage + straw returning (TS), no-tillage + no-straw returning (NT) and no-tillage + straw returning (NTS). The results showed that the organic carbon storage (SOCs) and total nitrogen storage (NTs) of no-tillage were increased by 3.1%-4.5% and 9.3%-11.9% compared with traditional tillage under the same straw treatment, and the organic carbon storage (SOCs) and total nitrogen storage (NTs) under the same tillage treatment were increased by 5.3%-7.6% and 9.1%-11.8% compared with non-tillage treatment. Compared with T, SOCs and NTs were significantly increased under no-tillage straw returning, among which the reserves under NTS treatment were the highest, reaching 14.65-14.98Mgha^-1 and 1.44-1.46Mgha^-1 . It was also found that the contents of organic carbon and total nitrogen were distributed in the order of (< 0.25mm) > (0.25-1 mm) > (1-2 mm) > (>2mm), and the contribution of large aggregates > 0.25mm to soil organic carbon and total nitrogen was the largest, and decreased with the depth of soil layer. Compared with T, NTS increased by 15.2%-23.5% and 25.3%-42.1%. No-tillage straw returning increased SOCs and NTs mainly because the content of large aggregates was increased by 0.25-1 mm, and the mean weight diameter (MWD) and geometric mean diameter (GMD) of soil aggregates were increased, the fractal dimension (FD) was decreased, and the stability of aggregates was increased. The structural equation model showed that the stability of large aggregates >0.25mm was significantly positively correlated with carbon and nitrogen storage, and the increase of soil carbon and nitrogen storage depended on the increase of carbon and nitrogen content in soil aggregates. Both no-tillage and straw returning were beneficial to improving soil aggregate stability and increasing soil carbon and nitrogen storage in farmland. Among different combined treatments, NTS treatment had the best effect on soil improvement, and the increase of soil carbon and nitrogen storage depended on the increase of carbon and nitrogen content in soil aggregates.