Abstract: Thanks to the high efficiency, excellent time resolution and large coverage with low cost, the multi-gap resistive plate chamber (MRPC) detector is a good detector choice for muon tomography technology. Improving the position resolution of the MRPC detector has been the focus of our research in recent years. In this paper, ANSYS Maxwell was used to calculate the three-dimensional electrostatic weighted field for MRPC detector. Based on the weighted field calculated, the effects of grounding of the back layer of the readout board, the readout strip pitch and the ratio of strip width in strip pitch on position resolution of the MRPC detector were studied for the same detector structure. Some design suggestions for improving MRPC’s position resolution that the readout strip pitch is 1 mm and the ratio of strip width in strip pitch is 50%-60% were given.