Sensor system of surface plasmon resonance (SPR) and measuring method thereof

A sensor system of a surface plasmon resonance (SPR) for analyzing a characteristic of a substance, comprising:

• an optical device for generating a first light beam and a second light beam in sequence;
• a sensor device mounted between a first dielectric layer and a second dielectric layer for respectively generating a first plasmon wave and a second plasmon wave in response to an optical characteristic change of said first light beam and said second light beam with respective to said substance, wherein said substance is disposed between said sensor device and said second dielectric layer, and a resonance is generated from said first plasmon wave and said second plasmon wave respectively generating a first reflective signal and a second reflective signal in response to a refractive index difference between said first dielectric layer and said second dielectric layer;
• and
• a measuring device for measuring spectra of said first reflective signal and said second reflective signal and obtaining a measured value, wherein said measured value is substituted into an operational formula to calculate a reference value used for analyzing said characteristic of said substance.