The utility model discloses a tap lead-out protecting device. The tap lead-out protecting device is characterized by comprising front and rear copper end covers, wherein a central cavity is arranged on each of the front and rear end covers; an inner plane step and an outer plane step along the radial direction are formed on the front end cover; an outer thread is arranged at the front part of the front end cover and connected to the inside of a tap screen housing through a thread; an inner thread is arranged at the rear part of the front end cover; the central cavity is also arranged on the rear end cover; an inner plane step and an outer plane step along the radial direction are formed on the rear end cover; the front part of the rear end cover is connected with the inner thread at the rear part of the front end cover through the outer thread; the central cavity of the front end cover and the central cavity of the rear end cover are coaxially communicated to form an overall protecting cavity; the outer thread is arranged at the rear part of the rear end cover. The tap lead-out protecting device can prevent connection of an outgoing line from being damaged by external force, and a test result is prevented from being easily interfered; the requirements of live detection are met.