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