Focused on the problem of phase ambiguity when using phase interferometer to estimate the direction of arrival, a new ambiguity resolution method based on rolling phase interferometer was proposed. The performance of this method was analyzed and compared with other methods by simulation. Finally, the hardware scheme of direction finding system was given, which solved the contradiction between the angle range and the direction finding accuracy in the interferometer of single base line, and can realize the direction finding of wideband under the condition of guarantee the direction finding accuracy. Moreover, it only needs two receiving channels and smaller volume. The result of computer simulation and the actual direction finding system show that the algorithm is effective.