Abstract: The application of chemical dispersants is considered as an effective method in oil spill response. In this study, we conducted experiments for evaluating chemical dispersants efficacy on PL19-3 and LD10-1 crude oils in a wave tank. The dispersant effectiveness and volume median diameter d50 were chosen as the indicated index, and two kind dispersants were tested under different wave conditions and dispersant to oil ratios(DOR). The results showed that the effectiveness of dispersant A and dispersant B on two crude oils increased aswave height and DOR increase, butd50decreased as wave height and DOR increase. The effectiveness of dispersant Bon PL19-3 crude oil was higher than dispersant A, with the highest effectiveness was 52.9% andthe smallest d50was 12m.For different types of crude oil, the dispersant efficacy was alsodifferent. The results of this study can provide a basis for dispersant efficacy prediction and emergency plan development for oil spill response.