The humpback whale’s pectoral fin has special leading-edge protuberances. This unique structure improves the performance of the pectoral fin. In this study, we employed this biological characteristic as the passive fluid control device on a 25 kW horizontal axis wind turbine. The wind turbine blades used in present study are based on FX63 with the rotating diameter of 12.4 m, the rated wind speed of 12 m/s and the rated speed of 60 rpm. By employing the dimensionless analysis, it shows that at 5 degree pitch angle, Cp and TSR can have 17.67% and 13.42% increments when the turbine blade was equipped with leading edge protuberances. Moreover, the output power variation can be reduced from 87.4% to 41.9% when ambient wind speed is 8 m/s. In the case of the starting wind speed is 4 m/s, the output power can be increased from 786.46 W to 1.5 kW. From the present experimental results, the leading edge protuberances effectively stabilize the wind turbine output power and increase the average power output. By investigating the relations of the power generation at different pitch angles and ambient wind speeds, it is also found that the present device can also stabilize the output power in the optimal Cp-TSR relationship at some fixed pitch angles.