Obtaining the cable partial discharge fault location quickly and accurately is of great significance to the safe and stable operation of the cable system. In order to resolve the problem of the traditional traveling wave positioning method on time synchronization,a double-ended positioning of partial discharge for cable based on variational mode decomposition-Wigner Ville distribution (VMD-WVD) phase method is proposed to reduce the influence of reflected waves identification in long-cable. It is marked the wave head of the double-ended partial discharge signal accurately to achieve the synchronization of the double-ended partial discharge signal by the proposed method. Through phase positioning,the advantages that synchronizing the incident signal of double-ended partial discharge in the long cable are realized. It is built a PSCAD model of a long line to analyze the positioning accuracy of the VMD-WVD phase method under the influence of fault location,cable length and sampling rate in long cables. The results show that the average positioning accuracy by the VMD-WVD phase method for the above three influencing factors is 0.54%,0.85% and 0.69% respectively,which is higher than the value by the traditional traveling wave positioning method. The research results provide a new idea for the precise positioning of partial discharge in long cables.