The utility model discloses an abdominal external noninvasive fetal oxyhemoglobin saturation detection device. The device comprises an extraabdominal fetal oximeter and a signal detection assembly connected with the extraabdominal fetal oximeter, the extraabdominal fetal oximeter comprises a signal processing controller, the signal detection assembly comprises a light-emitting light source device.The light receiving device comprises a plurality of light receivers which are respectively arranged at a plurality of different positions outside the abdomen of the pregnant woman; the system also comprises an adder connected with the plurality of optical receivers. The adder is connected with a signal processing controller of the abdominal external fetal oximeter; the light receiving device collects a plurality of light signals which are scattered and reflected back from the abdomen of the pregnant woman and related to the fetal blood oxygen saturation degree through a plurality of light receivers, and outputs the sum of the light signals related to the fetal blood oxygen saturation degree to the signal processing controller after the light signals are superposed by the summator, so thatthe intensity of the received light signals is improved.