Magnetic polariton (MP) that couples electromagnetic waves with magnetic excitation can be predicted by equivalent inductor-capacitor (LC) circuit model. However, when the resonance frequencies of MP and surface phonon polariton (SPhP) is close, the absorption peak predicted by the previous LC circuit model are far different from solving electromagnetic field calculation results. Absorption enhancement with a SiC slit array is theoretically demonstrated within the SiC phonon absorption band with Finite-difference time-domain (FDTD) method. The electromagnetic field distributions confirm the interactions between SPhP and MP. Taking the effects of interactions between MP and SPhP into account, the improved LC circuit model is employed to predict MP1 resonance condition and the method for predicting the multi-order MP resonance conditions is given. This study may contribute to the oriented design of thermal radiative properties and micro/nanostructures metamaterials thermal radiative properties database building.