In order to obtain a correct phase unwrapping (PhU) result,as well as to alleviate the effect of noise,a novel quality map is proposed. Firstly,some disadvantages of phase derivative variance (PDV) quality map and modulation map are analyzed. Then based on isotropic gradient amplitude,some methods about image sharpening and modulation are combined to construct a new quality map. The new map is named “Modulation-Roberts Gradient Amplitude Variance” quality map (MRGAV). In the applications,the computer simulated and the experimental data are offered. The comparison between the MRGAV quality map and the PDV quality map shows that the MRGAV quality map is not only more reliable,but also can overcome the drawbacks of the PDV and some other traditional quality maps successfully.