We report on the development and characteristics of a planar waveguide sensor system based on surface plasmon resonance (SPR) phenomenon. The designed planar waveguide consists of Cr-, Au-thin films and fused silica substrate. Firstly, we investigate the sensing performance of the proposed SPR waveguide using analytical simulation. And, we measure SPR curves of four different sucrose solutions, having variable refractive index from 1.333 to 1.34 corresponding from 0 to 50,000 ppm in concentration. Finally, comparing the experimental result to the simulation result, we present the SPR planar sensor system can be applied to fabrication process of food, medicine and chemical industries.