The planar two-dimensional grating displacement measurement technology is difficult to achieve balance between high precision and large range. To address this issue, a two-dimensional electric field time grating displacement sensor with a discrete array structure is designed, which is based on the research foundation of the one-dimensional electric field time grating in the early stage. A coding method of planar orthogonal discrete grating surface spatial arrangement is utilized in the sensor to realize the coding of planar two-dimensional electric field time grid excitation electrodes. A planar two-dimensional electric field time grating displacement measurement model is formulated, and the coupling signal expression modulated by the displacement information in the X and Y directions is theoretically deduced. A method for direct decoupling of two-dimensional displacement measurement signals is proposed, which uses the spatial position relationship of differential sensing electrodes to realize the decoupling of measurement signals through simple addition and subtraction operations. The sensor prototype is established by using PCB technology and performance tests are implemented to evaluate the feasibility of the proposed coding and decoupling method. The final result shows that the sensor proposed in this paper has the peak - to - peak measurement errors of 13. 1 μm and 11. 8 μm in X and Y directions respectively in the measurement range of 160 mm×160 mm.