In order to make the refractive index sensor has high quality factor and high sensitivity, a one-dimensional photonic crystal microring resonator based on a grooved optical waveguide is proposed. In this structure, the light modes of two different states interfere with each other in different optical paths to produce in Fano resonance. This asymmetric linear structure can obtain higher extinction ratio and quality factor, and it also has better sensitivity in refractive index sensing. The structure is analyzed and simulated by using finite-difference time domain method. The simulation results show that the quality factor of the proposed structure reaches 30950, which is more than 4 times higher than the traditional microring resonator, and the extinction ratio is 29.08 dB, which is 16.89 dB higher than that of the traditional microring resonator. In the analysis of refractive index sensing characteristics, the sensitivity of the proposed structure reaches 344 nm/RIU, which is 3 times higher than of traditional microring resonators, and the lower limit of sensitivity detection is 1.4×10 ^-4 RIU.