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 a first distance is 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 corresponding to the frequency spectrum signal through a machine learning module and transmits the stenosis percentage to the sensing device.本發明提出一種動靜脈瘻管狹窄偵測系統及其方法及感測裝置。動靜脈瘻管狹窄偵測系統，包括：感測裝置，包括麥克風；以及伺服器耦接到感測裝置。感測裝置接觸病患身體的第一位置，其中第一位置與病患身體的動靜脈瘻管的第二位置之間具有第一距離，且第一位置位於對應動靜脈瘻管的動脈或靜脈的延伸路徑上。感測裝置透過麥克風接收頻譜訊號並傳送頻譜訊號到伺服器。伺服器透過機器學習模組來計算對應頻譜訊號的動靜脈瘻管的狹窄百分比，並傳送狹窄百分比到感測裝置。
