The invention provides a piezoelectric MEMS acoustic sensor, which comprises a substrate, an internal electrode area and an external electrode area. The external electrode area is arranged at the periphery of the internal electrode area. Each of the internal electrode area and the external electrode area includes a top electrode, an upper piezoelectric layer, an intermediate electrode, a lower piezoelectric layer and a bottom electrode which are stacked from top to bottom. The top electrode, the intermediate electrode and the bottom electrode in the internal electrode area are spaced apart from the top electrode, the intermediate electrode and the bottom electrode in the external electrode area. A lower supporting layer is arranged at the top of the substrate; the internal electrode area and the external electrode area are both arranged on the lower supporting layer; and upper supporting layers made of silicon-based materials are arranged on the top face of the internal electrode areaand the top face of the external electrode area. The piezoelectric MEMS acoustic sensor has advantages of high sensitivity and enhanced hydrostatic pressure resistance; and the MEMS acoustic sensor can meet the application requirements of different pressure resistance and working water depths.