In this paper, the working principle of eddy current sensor used for displacement vector sensor is analyzed; the sensing coefficient of eddy current sensor is studied. The influence of each parameter of eddy current probe coil on the sensing coefficient is obtained, and the calculation model of the sensing coefficient is verified by experiments. The directivity resolution of eddy current displacement sensor is studied, and the simulation is carried out by using finite element software. The ratio of the sensing coefficient of the spindle direction to the sensing coefficient of the spindle direction orthogonal direction has been obtained. The ratio increases with the increase of the radius of the metal body to be measured and is greater than 20 dB, which meets the requirements of directional resolution of the vector hydrophone.