In this paper, a silicon waveguide integrated accelerometer based on cavity optomechanical system is proposed. The accelerometer can be fabricated on SOI wafer with top silicon thickness of 250 nm by micro nano processing technology. The structure and working principle of the accelerometer are analyzed. The optical mode and transmission characteristics of the photonic crystal microcavity structure and silicon waveguide structure of the accelerometer are simulated. The edge coupling of silicon waveguide, the coupling between silicon waveguide and photonic crystal waveguide, and the coupling between photonic crystal waveguide and photonic crystal microcavity are simulated. According to the simulation results, the overall optical path loss is less than 18 dB. Due to the use of the simplest mode transformation structure, the processing technology of the integrated silicon waveguide cavity optomechanical accelerometer can be greatly simplified.