With the miniaturization and integration trend of the integrated circuit and optical devices, and the realistic requirement of building large-scale photoelectric integrated system, a parallel-coupled dual-microring resonator configuration is designed. The method of finite difference time domain (Finite Difference Time Domain, FDTD) was employed to analyze the impact of key geometry parameters (the center-to-center (Center-To-Center, CTC) distance, the gap width and the change of waveguide refractive index) of the model on the origin and characteristics of coupled-resonator-induced transparency effect (Coupled Resonator Induced Transparency, CRIT) in the reflection spectrum. As the red shift of the reflectance spectra induced by the slight refractive index (RI) change of cladding part, this model can be used as a RI sensor with the sensitivity of 223.3 nm/RIU (refractive index unit), which is 2.8 times as high as the value of the single ring model.