surface plasmon resonance (SPR) sensors have become a central tool for characterizing and quantifying bimolecular and drugs interactions. In this article first we have reported the processes of designing and manufacturing of our new homemade SPR sensor. Then by means of constructed sensor the refractive index of three mediums have been measured. Based on both experimental and simulated results, our SPR sensor can be used as refractive index sensor for liquid mediums (gas mediums) with sensitivity of 8×10^-4 RIU (1.5×10^-3 RIU).