A new scheme to achieve high resolution in passive millimeter wave imaging (PMMWI) using electromagnetic (EM) vortex beams is proposed in this article. The spatial resolution of the traditional PMMWI system based on the mechanically or electronically controlled scanning scheme is mainly limited by the beam width of the receiver. However, it is not practical to fabricate an antenna that is too large, another possible way to improve the resolution is to increase the sampling points but will increase the imaging time. In this article, the multimode EM vortex beam is applied to achieve high resolution with less sampling points. The imaging scene is first discretized into small grid cells, and then multimode measurements are conducted during the scanning process to construct equations to solve the unknown brightness distribution. The compress sensing method is applied to reduce the number of orbital angular momentum mode. Simulation results demonstrate that high resolution can be achieved by the proposed method.