To improve the sensitivity and quality factor in refractive index sensing, a grating-assisted slot microring resonator is proposed. On the basis of the slot microring, the grating structure is introduced to realize the electromagnetically induced transparency (EIT)-like effect at different wavelengths, and obtain higher sensitivity and higher quality factor. A numerical model for spectrum calculation and parameter optimization of the hole-embedded microring resonator is built by the transfer matrix method. The transmission spectrum of the proposed device structure and electric field distribution of the resonator are simulated using the finite-difference time-domain (FDTD) method, and the influence of device structure parameters is discussed. The results indicate that the proposed device achieves the EIT-like. In the application of refractive index sensing, the quality factor of the proposed device is 35495, and the sensitivity is as high as 360 nm/RIU (RIU is refractive index unit). Compared with the results of the conventional microring resonator with similar parameters, the sensitivity is improved by 270 nm/RIU, and the lower limit of sensitivity detection of the proposed device is 2.3×10^-4 RIU.