Silicon photonics circuit has been widely investigated in recent years, due to its advantage in the small footprint, high density integration and compatible with CMOS pilot line. In this paper, a compact, highly-sensitivity NaCl concentration sensor is experimentally demonstrated, based on the micro-ring resonators. The sensor circuit is composed of grating couplers, bus waveguide and micro-ring resonators. The width of optical waveguides is 450nm, with a thickness of 220nm. The chip was fabricated in imec through the ePIXfab multi-project wafer service supported by our group, which is compatible with the CMOS process line. The chip shows high sensitivity, as high as of more than 80nm/RIU, which corresponding to a detection limit of 1.6e-4 by using optical spectrum analyzer.