The invention relates to the field of electrical equipment test equipment, in particular to a power cable sealing device which comprises a supporting element, a sealing element, a fixing element, a test interface and a detection element. The sealing element is arranged in a U-shaped structure. The two side walls of the sealing element are arranged in close contact with the axial surface of the endpart of the cable so as to ensure the sealing performance between the two side walls of the sealing element and the axial surface of the end part of the cable. The supporting element is arranged at the bottom of the sealing element and is arranged in abutment with the transverse section of the end part of the cable and is used for isolating the end part of the cable from the bottom of the sealingelement to protect the sealing element. The fixing element and the sealing element are arranged correspondingly and are used for ensuring the sealing performance of the sealing element. The supporting element, the sealing element and the fixing element correspond to the cable to form a closed air flow passage which is used for providing a test interface for the sealing performance of the cable. The test interface is arranged to be corresponding to the closed air flow passage. The detection element is arranged in the test interface and used for detecting the water inflow and moisture inside the cable.