In order to facilitate subsequent processing, this paper proposes a polarization-insensitive terahertz dual-band narrowband absorber, its unit structure is a metal resonance layer-dielectric layer-metal substrate layer, with a area of 25 μm×25 μm and thickness of only 3 μm. Through the S parameter, the relationship between the size parameter of the device unit structure and the resonance frequency and absorptance is analyzed. The simulation results show that the absorption rate of the absorber at the resonance frequencies of 1.508 THz and 2.464 THz are both above 98.8%, and there is no limit to the polarization mode of the incident electromagnetic wave, and the good absorption performance is still maintained in the incident angle range of 0°~40°.