The objective of this paper is to design a refractive index based photonic quasi crystal fiber biosensor involving surface plasmon polariton. We investigate the loss spectra for three different refractive indices of the analyte, na. Using finite element method, we infer that the proposed sensor shows a maximum refractive index sensitivity of 1500 nm/RIU and a good resolution of 6.66 × 10-5 RIU when na is increased from 1.54 to 1.56. Further, selective filling of liquid in the selective holes has been carried out for the proposed biosensor over a sensing range from 1000 to 1060 nm wavelength. We envisage that the proposed sensor would be a promising tool for bulk sensing applications.