In this paper, we proposed a high sensitivity and high resolution surface plasmon resonance biosensor based on WS2 nanomaterial, methylammonium lead iodide (MAPbI3)perovskite nanosheet and Au-Ag bimetallic film. The structure is based on Kretschmann configuration with six layers. Our proposed sensor can behave linearly upto 0.02 RIU change in sensing medium. The highest sensitivity was calculated as 195 (Deg/RIU) with full width at half maximum (FWHM) of 7.6 Deg. We also proposed another structure to get higher resolution of 6.3 Deg FWHM with a sensitivity of 187.5 (Deg/RIU). Both of our proposed designs are far superior in responsivity and sensitivity to pure Au based biosensors.