The absorption performance of the metamaterial absorber based on common split ring resonator (SRR) is firstly simulated using the CST microwave studio software. Then, according to the surface current distribution, the equivalent circuit models of the metamaterial absorber for the incidences of transverse electric (TE) wave and transverse magnetic (TM) wave are set up. Finally, the equivalent circuit models are theoretically verified. At the same time, by using the equivalent circuit models, the influence of geometric parameters on the change of absorption peak position is discussed. The proposed equivalent circuit models are very important for the structure design and performance analysis of the metamaterial terahertz absorber.