When interferometer algorithm works, it uses the phase differences of signal and the phase differences in local data to calculate the DOA. The interferometer direction-finding method has been widely used in engineering because of its flexible and the small amount of calculation. However, because of the array fabrication errors and the receivers’ inconsistent of phase, the accuracy of interferometer could be strongly affected as the calibration effect of local phase samples will fail when time-changing phase errors in present. Aiming at improving the algorithm stability in phase interference, we propose a refinement method of interferometer algorithm based on the response anisotropy of array and its optimized version, both of which improve the algorithm accuracy and weaken the dependence on the system’s phase consistency. Furthermore, computer simulation verifies that under the condition of different phase errors, the average directional error of the optimized interferometer algorithm is reduced to 38% compared with traditional interferometer algorithm, which shows that the accuracy and stability of the interferometer algorithm are significantly improved under interference conditions.