An intercepting user equipment and a lawful interception method thereof are provided. The intercepting user equipment registers to the administrating server for lawful interception, and then receives a positive interception message from the administrating server. The intercepting user equipment receives a signal from user equipment, and determines whether a power measurement of the signal exceeds a threshold. If positive, the intercepting user equipment transmits a power adjustment request to the administrating server so that the administrating server notifies the eNB of transmitting a power adjustment command to the user equipment for adjusting transmitting power. The intercepting user equipment intercepts communication data of the user equipment.