A new multiple-taps and flat microwave photonic filter, which is composed of fiber Bragg grating, M-Z modulator and erbium-doped fiber, is put forward. The flat band-pass or flat band-stop response can be realized by adjusting the coupler’s factor and the reflectivity of the fiber Bragg grating or the gain of the erbium-doped fiber. The free spectral range of the filter can be tuned by controlling the length of the erbium-doped fiber. The potential and feasibility of the proposed filtering structures have been demonstrated by simulation. This project has been jointly supported by the National Natural Science Foundation of China (No. 60771008, 60837002), the Beijing Natural Science Foundation (No.4082024), the Foundation for the Returning Scholars (No. 2008890) and the Ph.D. Program Foundation, Ministry of Education of China (No. 200800040002)