The working performance evaluation rate of a wave energy generator is closely related to the characteristics of wave energy resources in the sea where it is located, and the calculation method of wave energy input. Based on the working principle of the Eagle wave power generation device, the relationship between the Angle of incident wave and the angle of wave energy captured by the wave absorbing float is analyzed, and the calculation method of effective wave energy power density acting on the wave energy generation device is studied. Based on the design scheme of WEC, the input wave energy power model is constructed. In order to verify the accuracy of the model, the real sea state data of Eagle wave power generator “Wanshan” for 217 consecutive hours are taken as an example, and the real-time input wave power of the device is calculated. The results show that when the effective wave height range is [0.5m, 1m], the results of the two methods are basically consistent in trend and value. When the effective wave height is higher than 1m, the literature results are larger than the calculated results in this paper, and the data gap of about 51.15% is between 10-15%, and the data gap of 24.88% is between 15-20%. The research results of this paper can provide reference data for the design and performance evaluation of WECs.