The optomechanical cavity accelerometer based on photonic crystal microcavity combines the mechanical resonator with the high-quality factor photonic crystal cavity, and the mechanical vibrator is sensitive to weak force/displacement in the mechanical vibration mode, which can achieve extremely low noise level and theoretically reach the standard quantum noise limit, which is an important direction for the development of high-precision accelerometer. This paper analyzes the principle and structural characteristics of the zipper type photonic crystal cavity optical-mechanical accelerometer, and designs a silicon-based zipper type photonic crystal cavity and mechanical vibrator structure for accelerometer. The influence of the structural parameters of the zipper cavity on the optical Q factor is analyzed in detail. The resonant frequency of the optical cavity is controlled around 195 THz by adjusting the structural parameters, and the mechanical resonance characteristics of the mechanical vibrator and the optical cavity are analyzed. The effective mass of the optical cavity is 30 pg, plus the effective mass of the mechanical vibrator is 3.1 ng, and the opto-mechanical coupling rate reaches the order of GHz/nm, which provides guidance for the manufacture and characterization of the silicon-based zipper cavity accelerometer.