Abstract: In order to investigate the effects of organic materials returning on the pore structure of meadow soil and maize yield, a field experiment was conducted in 2019 in Gongzhuling City, Jilin Province. In this study, four treatments including straw incorporation within 0 - 15 cm soil depth (CT) and 0 - 35 cm soil depth (STS), straw and organic manure incorporation within 0 - 35 cm soil depth (STSM) and conventional practice without organic material incorporation (CK) were selected for experimentation. Sampling and analysis were carried out after the maize harvest in 2019 to determine the soil physical properties and pore structure at the soil layer of 0 - 35 cm. The structural equation model, Mantel test, and random forest method were used to analyze the regulatory pathways of soil pore structure to maize yield. The results showed that compared with the CK treatment, the soil bulk density at the 0 - 15 cm soil layer with CT, STS and STSM treatments significantly decreased by 5.2% - 7.8% (P<0.05); whereas the field water holding capacity and saturated hydraulic conductivity significantly increased by 7.8% - 16.6% and 77.5% - 325% (P<0.05), respectively. The STS and STSM treatments significantly improved the above three soil physical properties at the >15 - 35 cm soil layer. The CT scanning results showed that the return of organic matter significantly improved the soil pore distribution and structure in the corresponding soil layer. Compared with the CK treatment, the CT, STS and STSM treatments significantly increased the number of >1 000 μm pores and porosity at the 0 - 15 cm soil layer; compared with the CT treatment, the STS and STSM treatments significantly increased the number of >1000 μm pores and porosity at the >15 - 35 cm soil layer by 1.2 to 1.3-fold and by 47.5% to 58.9%, respectively (P<0.05). Returning organic materials to the field increased the complexity and connectivity of soil pores. Compared with the CK treatment, the CT, STS and STSM treatments significantly increased the anisotropy and fractal dimension and decreased the Euler number at the 0 - 15 cm soil layer (P<0.05); the STS and STSM treatments significantly improved the soil pore structure at the 15 - 35 cm soil layer. The results of structural equation modeling showed that the soil pore structure at the 0 - 15 cm soil layer may directly affect maize yield or indirectly affect maize yield by influencing the bulk density and saturated hydraulic conductivity, while the soil pore structure at the 15 - 35 cm soil layer may only indirectly affect corn yield by influencing the water holding capacity of the field. Soil physical properties and pore structure explained 81.9% of maize yield, and the 15 - 35 cm soil layer contributed more to maize yield than the 0 - 15 cm layer. The deep mixing of organic materials returning exhibits a potential to improve maize yield by improving the physical properties and pore distribution of meadow soil at the 0 - 35 cm soil layer, increasing the complexity and connectivity of pore structure, and optimizing the structure of the tillage layer. The effect of the combined application of straw and organic matter is better than that of straw return alone. It is suggested that in the meadow soil region, deep mixing of straw and organic fertilizers returning would build up good soil fertility and effectively increase the maize yield.