In the solar electric vehicle, the photovoltaic cell charges the battery through a unidirectional converter and the battery supplies power to the load through the inverter circuit. When the load changes suddenly, the charging and discharging of the battery will change suddenly, which will seriously affect the service life of the battery and even be irreparable until it is scrapped. In addition, the load mutation is regarded as mismatched disturbance in the solar vehicle electric inverter, and the inhibition effect of the traditional control method is not ideal. In this brief, a repetitive control based on mismatched disturbance observer (RC-MDO) is proposed. The mismatched disturbance observer is used to estimate the mismatched disturbance and construct a new disturbance compensation gain to eliminate the influence of the load mutation from the output voltage channel. Meanwhile, the repetitive control also has inhibition effect on the disturbance, so that the dual inhibition of the disturbance can be realized. Compared with the traditional PI control and repetitive control, it can effectively reduce the fluctuation of output voltage, suppress voltage drop and improve the stability of the system.