Ridge tillage is one of the essential tillage methods in China. It affects the soil structure by altering the soil-water environment. With the rapid development of agricultural mechanization, the mechanized ridge tillage technology that combines modern mechanized agriculture with conservation tillage has become a pertinent agricultural production technology in the hilly regions. However, to date, the effects of mechanized ridge tillage on soil structure have garnered little attention. In this study, a field plot experiment involving the following four treatments: conventional tillage with rice and winter fallow (CK1), conventional tillage with rice-rape rotation (CK2), wide ridge tillage with rice-rape rotation (BT), and narrow ridge tillage with rice-rape rotation (RT) was conducted to study the effects of mechanized ridge tillage with rice-rape rotation on soil aggregate stability and soil porosity. The results indicated that mechanized ridge tillage could reduce the porosity of pores > 30 μm in diameter and increase the porosity of pores < 0.5 μm. Furthermore, mechanized ridge tillage could increase soil aggregate stability; the order of average mass diameter and geometric average diameter was RT > BT > CK2 > CK1. The BT and RT treatments could increase the agglomeration degree of the soil particles, which followed the order of RT > BT > CK2 > CK1. Therefore, mechanized ridge tillage with rice-rape rotation is effective in enhancing soil structure.