The impedance matching is a very important part to influence materials' microwave absorption performance. However, a way to further discuss the impedance matching is still weak. We build a novel dielectric-magnetic impedance matching (DMIM) model to analyze the real part and imaginary part of materials' impedance matching. To verify the practicality of the DMIM model, using MIL-100(Fe) as precursor, a series of FexNi1-x@C are synthesized via one-step pyrolysis by controlling the samples' Fe-Ni ratio, changing their dielectric loss tangent and magnetic loss tangent and successfully regulating their impedance matching to optimize microwave absorption properties. In addition, the minimum reflection loss for MOF-derived Fe0.8Ni0.2@C can arrive at -71.3 dB at 10.3 GHz with a thickness of 3.1 mm, and the effective absorption bandwidth is 5.3 GHz. And combining with the RLGC equivalent circuit model to further indicate the FexNi1-x@C's energy loss mechanism. The method of using DMIM model and RLGC model to discuss materials' impedance matching and energy loss mechanism paves a new way to fabricate high-performance microwave materials with balanced electromagnetic distribution and further reveal the materials' microwave absorbing mechanism. [GRAPHICS] .