In order to verify the feasibility of underwater power transmission and study the factors affecting the transmission efficiency, a simple wireless charging circuit is designed based on the principle of electric field coupling. The system structure and basic working principle of electric field coupled radio power transmission are introduced, and its characteristics compared with magnetic field coupling mode are analyzed, as well as the corresponding advantages. The distribution of electric field between plates is simulated by multi-physical field simulation, and a double-sided CPT system of LC is designed, which uses a single-chip microcomputer to form a pulse width modulation control circuit and power amplifier circuit modules to form the transmitting end and the receiving end. The results shows that using electric field coupling principle for wireless charging is feasible, the transmission distance between the plates is a factor affecting the underwater wireless charging efficiency, and the stray capacitance between the two electrodes also affects the power between the plates, so the power loss between the plates is largely due to the plate gap. The LC bilateral CPT system proposed in this paper not only realizes underwater radio power transmission, but also ensures the stability of transmission efficiency at a certain distance and frequency.