This research is devoted to optimizing PCB with simulation technology to improve its anti-electromagnetic interference ability. Based on the ANSYS SIWAVE simulation platform, we focus on identifying and solving problems that PCB may face in electromagnetic environments to improve system reliability and performance. First, the potential resonant frequencies and electromagnetic radiation points are identified through the modal analysis and frequency domain analysis of PCB. Then, the resonant frequency point is eliminated by adding decoupling capacitors The wiring scheme is adjusted, the signal transmission path is optimized, and the key signal lines are protected by simulation research on the high-speed signal aperture, which reduces the risk of signal distortion and timing problems. The simulation results show that these optimization measures have achieved remarkable results in improving PCB performance and stability.