In order to explore the change characteristics of soil shear strength, change characteristics and influence factors of soil shear strength were studied during maize growing period based on the method of field investigation and laboratory. The result showed that in the 0～5cm soil layer, soil shear strength increased gradually with the maize growth period and reached the maximum in mature period. However, soil shear strength increased first and then decreased with the maize growth period in the 5～10cm and 10～15cm soil layers, and soil shear strength reached the maximum in tasseling period. Soil shear strength showed the higher values in the different maize growing periods. The reinforcing effects of the shear strength in the first three soil layers were the better, and the reinforcing rates were the highest in tasseling period of maize. There existed linear function between soil shear strength and the soil moisture, and there were significant positive linear correlations between soil shear strength and soil bulk density, root amount, root length, root volume. At the same time, there were significant positive correlations between the reinforcing values of the shear strength and increasing value of 0~1mm root length. Soil shear strength enhanced gradually with the maize growth period, and soil water content, bulk density and maize root had a great influence on soil shear strength. So, it had significant importance for soil erosion control to select the maize variety with 0~1mm root ,and applied soil and water conservation measures to increase soil water content and bulk density.