Abstract: The problem of large fluctuation of phase measurement in the tight field test of high frequency antenna is studied, and the reason of large fluctuation of phase measurement in high frequency case is analyzed through the basic principle of electromagnetic wave propagation in space. The position formula of the phase difference and the angle of the receiving antenna is derived combined with the size of the static area in the tight field. After that, the motor with suitable precision is selected in combination with the position formula to solve the error problem that cannot be solved in the mechanical angle, and the phase difference error compensation of the receiving antenna in the electrical sense is completed. Finally, a comparison test with the traditional method proves that the phase measurements before and after the adjustment change significantly, and the maximum phase difference measured is reduced from 17.4° to 4.78°, which shows that fewer additional errors are introduced that in the traditional method, and the real phase situation in the tight field can be better obtained.