In this paper, a wide-angle broadband perfect absorber is composed of a periodical metamaterial heterostructure. The structure is designed according to the concept that the metamaterial absorber's resonant frequency range can be manipulated by adjusting the filling factor of a bi-insulator heterostructure. The calculated results reveal that the four-layer herostructure has four perfect absorption peaks at the range of the terahertz frequency band. The related absorption bandwidth is 300 GHz and the average absorptivity is 98.6%. At the same time, the structure is insensitive to the incident angle.