Aiming to increase the sensitivity of a micro-electro-mechanical system （MEMS） micro-pressure sensor， the primary factors that influence sensor sensitivity were introduced according to the working principle of a silicon piezoresistive pressure sensor. Subsequently， simulations were conducted using the COMSOL Multiphysics software to analyze the influence of film thickness， optimal position， and length of the varistor. Based on the simulation results， the sensitivity of a 40 kPa MEMS micro-pressure sensor was optimized. The sensitivity of the micro-pressure sensor could be enhanced effectively by reducing the film thickness to 15 μm， setting the length of the varistor to 120 μm， and strategically placing the varistor 10 μm away from the edge of the film. The test results of the optimized sensor show that by optimizing the structure design， a sensitivity of 0.444 mV/kPa can be achieved for the MEMS micro-pressure sensor. The sensitivity of the optimized sensor is 26.8% greater than that of the standard sensor， which has a sensitivity of 0.35 mV/kPa. Thus， the system requirements of higher sensitivity and linearity can be satisfied using the optimized MEMS micro-pressure sensor.