An arteriovenous fistula (AVF) stenosis detection system and method thereof and sensing device are provided. The AVF stenosis detection system includes: a sensing device including a microphone； and a server coupled to the sensing device. The sensing device contacts a first location of a patient body, wherein there is a first distance between the first location and a second location of an AVF of the patient body, and the first location is located on an extended path of an artery or a vein corresponding to the AVF. The sensing device receives a frequency spectrum signal through the microphone and transmits the frequency spectrum signal to the server. The server calculates a stenosis percentage of the AVF corresponding to the frequency spectrum signal through a machine learning module and transmits the stenosis percentage to the sensing device.
