To investigate the healing behavior and healing occasion of cement stabilized macadam (CSM), the factors influencing the healing effect were analyzed based on the damage-healing model. Firstly, a 2D semicircular bending (SCB) numerical specimen of CSM was established through the Discrete Element Method (DEM). The damage factor was adopted to simulate the local damage and healing effect, and then the mesoscopic damage-healing model was constructed under a SCB loading mode. Secondly, the virtual SCB fatigue test was adopted to realize different degrees of load damage. The healing variable was established to simulate the healing behavior of local damage. Lastly, based on the damage-healing model, the healing effects were evaluated to reveal the influence of the initial damage state and healing degree of specimens. The optimal healing occasion of CSM was further studied. The results show that the proposed numerical damage-healing model can explain and simulate the mesoscale damage and healing behavior of CSM materials. The initial damage state and healing degree have nonlinear effects on healing effect. In the fatigue life stage of 70%-85%, local damage healing has a significant effect on strength improvement. According to the healing results, 70%-85% fatigue life is recommended as the optimal healing occasion for CSM materials. In addition, enough healing agent with moderate strength can help to maximize the healing effect of local damage.