A high sensitivity refractive index sensor based on surface plasmon resonance (SPR) with topological insulator (Bi2Te3) has been proposed theoretically. It is demonstrated that the presented sensor exhibits an extremely great sensitivity enhancement with angular and wavelength-interrogation modes compared to conventional SPR sensor by covering the topological insulator (Bi2Te3) on the gold thin film. In particular, the maximum sensitivity of wavelength-interrogated sensor can be further increased above 25% with 3 QL Bi2Te3 sheet. Moreover, in order to further increase the sensing performance, the few layers black phosphorus (BP) and cytop film are covered on 1 QL (a single Bi2Te3 crystal quintuple layer containing five layers of Bi and Te) Bi2Te3 to form a highly angular sensitive Bi2Te3-BP heterojunction, the maximum angular sensitivity can reach about 175 deg/RIU. Compared to the aforementioned Au-Bi2Te3 based SPR sensor, the sensitivity of this heterojunction-based SPR sensor is improved by 29%. With such improving performance, we believe that the configuration can be potentially used in the field of chemical and biological sensors in the future.