In view of the influence of waves on solar radiation characteristics of solar panels on a small Unmanned Surface Vehicle （USV），the attitude dynamic response characteristics of small USV under wave action and solar radiation characteristics of solar panels on USV under high-frequency unstable oscillations of attitude are studied.A Irradiance simulation calculation model of small USV is established，and the dynamic change of irradiance of solar panels on USV is analyzed according to the typical wave conditions and different solar altitude angle.The simulation results show that：the irradiance of solar panels on USV oscillates greatly due to the influence of the wave and solar altitude angle under the real sea condition，the maximum oscillation amplitude of irradiance decreases from 79.0% to 31.3% and 6.9% respectively when the solar altitude angle increases from low to medium and high；but the wave direction has little effect on the average irradiance，the deviation of the average irradiance caused by the wave direction does not exceed 3.57% when the solar altitude angle is the same.