There is limited amount of research on surface plasmon resonance (SPR) sensors with self-referencing capabilities which are based on dielectric gratings. In the short-wavelength range, a metal grating sensor is capable of simultaneously measuring liquid refractive index under proposed temperature. A fabricated gold grating is placed on one side of a thin gold film for refractive index measurement, while the other with polydimethylsiloxane (PDMS) is deposited on the other side for temperature measurement. We use finite element analysis to research its sensing characteristics. Due to the high refractive index sensitivity of SPR sensors and thermo-optic coefficient of PDMS, we discovered the maximum spectral sensitivity of the sensor is 564 nm/RIU and −50 pm/°C when the liquid refractive index ranges from 1.30 to 1.40 with temperature ranging from 0 °C to 100 °C. Numerical results indicate that there may not be mutual interference between two channels for measuring refractive index and temperature, which reduces the complexity of sensor measurements.