In order to expand the measuring range of flow sensor and reduce power consumption of the sensor, a MEMS flow sensor based on self heating amorphous germanium film thermistors was fabricated and tested. It is composed of four amorphous germanium film thermistors and a pair of environmental temperature measurement compensation thermistors, which are embedded in a silicon nitride film. The four amorphous germanium thermistors act as self heating heat sources and temperature measuring elements at the same time, and are connected with each other to form a Wheatstone bridge. The MEMS fabrication process is given, and the size of 8.9 mm × 5.6 mm × 0.4 mm of the flow sensor chip is fabricated by micromachining. The low velocity and high velocity airflow pipeline experimental devices were built. With constant current (CCA) of 50 μA supplied to the Wheatstone bridge of the flow sensor, the flow velocity measurement of 0~50 m/s is realized by test. The results show that the sensitivity of the sensor is about 81.6 mV/(m/s) when measuring 0-2 m/s low flow velocity, 51.9 mV/(m/s) when measuring 2-50 m/s high flow velocity, and the maximum power consumption is only about 1.03 mW.