A dual-core D-shape photonic crystal fiber sensor based on surface plasmon resonance is designed and analyzed numerically by the finite element method employing the perfectly matched layer boundary conditions. The resonance peaks shift as the analyte refractive indexes are varied. An average sensitivity of 17,200 nm / RIU is achieved in the RI range between 1.40 and 1.44 and the corresponding resolution is 5.8 × 10 ^{− 6} RIU. The various factors affecting the sensing properties are assessed and in particular, the combined effects of two variables are evaluated.