A novel nano electro mechanical system (NEMS) accelerated sensor which is based on piezo-resistive effect of GaAs/AlGaAs/InGaAs Pseudomorph-High Electron Mobility Transistor (PHEMT) has been designed and fabricated. The structures of sensor and sensitive element are described in this paper. The main process of Micro-machining is introduced in the text. The static press test has been performed and the testing results show that the NEMS accelerated sensor could sense exterior stress well. Then, a testing circuit is designed to detect the change of drain current under pressure. Through the vibration experiments of the sensor, the sensitivity has been discussed and given out. The conclusion that the sensitivity is maximizing in the saturation region can be got. And the measurement result shows that the sensor has good linearity and high sensitivity with 0.177mV/g in the saturation region.