A surface plasmon resonance (SPR) sensor based on a multi-core photonic crystal fiber (PCF) is presented in this paper. There is only one analyte channel positioned in the center of the PCF cross section, rather than several closely arranged analyte channels around the central core. So the design of this sensor not only reduces the consumption of gold and samples, but also effectively avoids the interference between neighboring analyte channels. Optical field distributions of this fiber at different wavelengths and the sensing properties of this sensor are theoretically analyzed and discussed using finite element method (FEM). Simulation results confirm that both the thickness of metallic layer and the fiber structural parameters have significant effect on sensing performance. The amplitude sensitivity of the sensor is found to be 1.74×10^-5RIU, and the spectral sensitivity is 3300 nm/RIU, corresponding to a resolution of 3.03×10^-5RIU. Finally, in order to achieve PCF-SPR sensing characteristics, an experiment design scheme based on spectroscopic detection method is proposed.