An eccentric reflective optical fiber micro-electro-mechanical system (MEMS) micro-pressure sensor is proposed in this paper. The core part of the sensor consists of a dual fiber collimator (a fiber collimator with two pigtails) in an eccentric position and a sensitive silicon diaphragm. The sensitive silicon diaphragm adopts the BM (beam-membrane) structure with small structural parameters manufactured by MEMS manufacturing technology. Simulation results show that the BM structure has good sensitivity and high natural frequency. Overall structure of the sensor with the measurement range of 0 ∼ 10 kPa is designed. The way of intensity demodulation ensures the performance and stability of the sensor and makes the sensing system easier to process signals. By building a static test platform and conducting experiments, we can conclude that the sensitivity of the sensor is −0.32 dB kPa−1. Furthermore, the repeatability of the sensor is 1.26%FS (full-scale), the hysteresis of the sensor is 0.95%FS and the zero drift of the sensor is 0.615%FS h–1. By building a dynamic experimental platform and conducting experiments, it can be seen that the response time of the sensor is 0.47 ms (<1 ms), the sensor has good dynamic response.