Based on the parameters such as the aspect ratio of the permanent magnet and the uniformity of the air gap magnetic field, the magnetic circuit of the quartz flexible accelerometer with Samarium-Cobalt permanent magnet (Sm2Co17) was designed using theoretical calculations and simulation analysis. The height ratio of the permanent magnet to the magnetic cap was adjusted, and the air-gap magnetic field of the two height ratios is measured. The one-month repeatability test was performed on the scale factor of the quartz flexible accelerometer with two different magnetic circuits. The results show that the optimized magnetic circuit can obtain the uniform air-gap magnetic field and maintain good long-term performance.