Optical feedback interferometry is a novel optical testing method. The self-mixing effect in laser diodes is a useful tool for testing the movement of a reflector and realizing high-precision measurement using a simple configuration. The operating principle of the optical feedback interferometry is introduced. Optical feedback interferometer experiments were carried out using a He-Ne laser and laser diode as light sources respectively, and the results were analyzed. The experiments validated the conclusion of the simulation. Discussion was made to the applications of optical feedback interferometry in MEMS sensing. A novel MOEMS accelerometer based on optical feedback interferometry was proposed. The accelerometer is simple and can make acceleration measurement with precision on a scale of light wavelength.