An improved mutual coupling modified projection method was proposed, based on the two stacked patches back cavity microstrip conformal array model. The method was applied for synthesizing the patterns of this kind of conformal array successfully. The amplitude and phase of the element exciting can be solved at one time, by means of introducing the generalized element pattern including the location information. Meanwhile, the concept of the element active pattern was combined with the least square method to simplify the solved process for mutual coupling matrix. Moreover, the phase pattern was also considered, which improved the reliability of the synthesis method. Besides, the perfect agreement between the synthesized results and full-wave method confirms the validity of the proposed method.