Ocean robots have important application value in both military and civil fields. However, ocean robots powered by batteries need to be launched and recovered frequently during mission due to the lack of continuous power supply. Capturing wave energy is a promising method to provide sustainable energy for ocean robots, despite that the existed wave energy converters (WECs) designed for ocean robots have limited power generation capacity. In this paper, we propose a deployable WEC for ocean robots to increase the wave energy capture performance in power generation mode and reduce the drag force in motion mode. The structure design and the power generation principle of deployable WEC are firstly introduced. Then, we establish the frequency domain and time domain dynamics models of wave energy harvesting. After that, a simulation platform based on the time-domain model is established to reveal the influence of wave amplitude, wave period, generator damping and the location of robot center of gravity (COG) on the dynamic response characteristics and wave energy capture performance. The results show that the highest capture width ratio of WEC can reach about 0.5 under the excitation of regular wave (T = 1.6 s, A = 0.02 m). The WEC proposed in this paper uses the deployable mechanism for on-board wave energy generation and overcomes the constraint of the size of the ocean robot on the power generation performance of WEC, which provides a new solution to the energy supply problem of ocean robots in the future.