The invention belongs to the technical field of cables and relates to a water seepage testing device of a cable. The water seepage testing device of the cable comprises a base, a water injecting barrel, connecting vertical post, a control and display unit achieving automatic recording, alarming and other functions, a first water outlet pipe, a first water outlet electromagnetic valve, a first connecting pipe and a water sensor, wherein the distance between the center line of the first water outlet pipe and the upper surface of the water injecting barrel is larger than or equal to 1 meter; in a test, one end of the cable is connected with the other end of the first connecting pipe in a water sealing mode and the water sensor is sleeved at the other end of the cable. The water seepage testing device of the cable mainly achieves that time can be automatically recorded in the water seepage test, alarming is performed when water seepage occurs, and automatic feeding is performed under the condition that part of water or all the water is lost. The water seepage testing device of the cable mainly has the advantages of being concise in equipment and easy to operate, human intervening is not needed, recording is truer and more reliable, time of testers is saved, labor intensity of the test is lower, and feedback of a result of the test is timelier.