[Research on designing MRI permanent magnet].

Based on the theory of magnet circuits, the paper introduces the process of designing MRI (Magnetic Resonance Imaging) permanent magnet. The measurement of magnet properties is improved by simulation technology. In order to increase the magnetic field homogeneity. We have designed a shim-loop and a trapeziform shim-board to optimize the magnetic field distribution. The results of both simulation analysis and experiments show that the innovative design improves magnetic field properties significantly and the magnet structure accords with the technology requirements.