Leak Detection System(LDS) is widely used to minimize the environmental damages and financial losses by discovering the leakage in its early stages. However, due to the long distance between sensors and immobility, existing wired stationary LDS has inherent limits in detection accuracy. In this paper, we present a wireless portable LDS which can find the leakage location more accurately than conventional LDS. The wireless portable LDS can transmit and receive pressure transient data in the pipeline via wireless communication(LTE/3G) in real time. Mobility of the wireless portable LDS allows us to narrow the suspected range of the leakage event step by step to minimize the detection error. Wireless portable LDS can be used either by itself or combined with existing LDS to improve the sensitivity. It is possible to operate more than 24 hours with equipped battery and also to be connected with power supply for continuous monitoring. This wireless portable LDS will be helpful to locate very small leaks as well as intermittent theft for the pipeline protection.