Abstract: The disclosure provides a pipeline leak detection device and a leak detection method based on the variational mode decomposition optimized by the particle swarm (PSO-VMD). The acoustic emission signals with leakage and without leakage are collected by the acoustic emission system. Since the decomposition result of the traditional VMD depends on the selection of the parameter preset scale K and the penalty coefficient ?, the PSO is employed to obtain the optimal parameters of the VMD. The optimized parameters are input into VMD to decompose the original signals, and then K intrinsic mode functions (IMFs) can be obtained. After the signal reconstruction for de-noising, based on the energy ratio, the time-domain features are extracted and the support vector machine (SVM) is used to detect the leak.