Phase unwrapping is a key step in InSAR processing. Among the existing methods, the Goldstein branchcut method is widely used, because its fast processing and good result. However, the branchcut method usually produces some “isolated area” which could not be unwrapped. Besides, it may cause large area error passing. This paper presents a qualityguided improved branch cut phase unwrapping method. This method uses quality map to guide the placement of branch cuts. Besides, in path following integrating process, quality map is used to guide the integrating path. Experiment shows that, this method is capable of avoiding “isolated area” and large area error passing. The proposed method is a combination of branch cut method and qualityguided path following method. It’s performance is better than those two methods.