Metamaterial absorbers are typically comprised by subwavelength split-ring resonators(SRRs) periodically distributed on the surface of some dielectric boarding substrates. Their absorptive rates are largely determined by the properties of the top SRRs and the material properties of the substrates. The transmission characteristics of metamaterial absorbers in terahertz wave were studied and the effect of PI thickness, cell size, width of the split ring resonator, conductivity of the top silicon and the dielectric constant of the PI medium on the position of absorption peak and absorption rate were analyzed by using the finite integration time domain(FITD) method. The characteristics of metamaterial absorber were expected to provide important reference for the design of terahertz modulator, filters, absorbers and polarizers.