Aiming at the effect of sea conditions on wave power device,the paper innovatively designed a new floating wave energy device, and described its working principle. Based on this device, the paper established the analysis model of energy collecting part.Based on the computer software of AQWA hydrodynamic performance,it calculated the RAO values under different drafts and floating body size, and a whole time domain response of wave direction and wave period as to the device. When the draft is between 1.3 to 1.4 meters and the diameter of float body is 2.8 meters, the RAO value can reach ideal value. The overall amplitude of floating body is larger under wave direction of 25 degrees and wave period of 3 seconds.The method can greatly improve the collection efficient of wave energy.