The invention discloses an acoustic emission positioning method of an underground gas pipeline leakage point based on Beidou positioning. The method comprises the following steps: 1, acquiring Beidou coordinates of a sensor based on a Beidou positioning system, and synchronizing time of all acoustic emission sensors; 2, sending the Beidou coordinates of acoustic emission sensors to an upper computer; 3, sending acoustic emission signals of pipelines to the upper computer; 4, recognizing leakage signals through a screening method based on support of vector machine; 5, determining a Beidou coordinate set of the leakage point by utilizing time difference positioning and amplitude attenuation positioning methods; 6, obtaining a Beidou coordinate of the leakage point by means of weighted mean. According to the acoustic emission positioning method disclosed by the invention, the acoustic emission positioning of the leakage point of the gas pipeline and a Beidou positioning system are combined, and the position of the leakage point can be calculated by adopting combination of time difference positioning, amplitude attenuation positioning and weighted mean, so that the accurate positioning of the underground gas pipeline leakage point with small flow can be realized.