A highly sensitive SPR-PCF based biochemical sensor has been proposed based on finite element method simulations. Two metal wires are assumed to fill into two air holes in the y direction and the liquid analyte with refractive index higher than background material is injected into the central air hole. The liquid analyte supports liquid-core mode which couples to SPP mode as the phase matching condition is satisfied. High sensitivity of fiber sensor is achieved by the direct interaction between transmitted light and liquid analyte. The fiber sensor possesses the sensitivities of −8383.9 nm/RIU, −8428.6 nm/RIU and –8776.8 nm/RIU by filling gold, silver and aluminium respectively into the air holes of the PCF as the refractive index of liquid analyte varies from 1.454 to 1.478. The influences of the structural parameters of the PCF on the resonance wavelength and confinement loss are also analyzed.