Red clay, an easily cracking lateritic soil, is extensively distributed in southern China. Cracked red clay slopes often show shallow failures under rainfall, which is challenging to reproduce by finite element methods. This study aims to examine how desiccation cracks and vegetation affect the shallow stability of a red clay cut slope during rainfall. Numerical models of the slope are created using ABAQUS, and an effective approach is proposed to simulate the distribution of desiccation cracks. The reliability of the numerical models and approaches is validated against field surveys. Parametric analysis is then conducted to investigate the influences of rainfall parameters, crack parameters and vegetation parameters on the slope stability. The results demonstrate that the presence of desiccation cracks can cause shallow failure and greatly reduce the factor of safety of the slope. This indicates that control of crack development is important to maintain slope safety. Moreover, the stability of cracked slopes can be obviously improved by vegetation with roots longer than 0.5 m. A tap root system appears to perform better than a fibrous root system. However, shallow-rooted vegetation may also contribute to the shallow stability of the slope by restraining the formation of desiccation cracks.