As one of the important electrical parameters to characterize the cable state, the accurate measurement of voltage is especially vital for the reliable operation of cables. To address the problems of complicated calculation of electric field in the vicinity of three-phase cables, too much reliance on historical experience, and the difficulty of three-phase voltage inverse calculation, this paper proposes a non-contact measurement method of three-phase cable voltage based on electric field inverse calculation. An optimal analytical calculation model of three-phase cable electric field distribution is established by combining the actual parameters of three-phase cable. An array of electric field sensors is made to obtain the electric field information of the cable neighborhood. A genetic algorithm is used to solve the electric field inverse calculation problem, which guarantees the global optimality of the solution results. The effectiveness of the proposed method is tested on a three-phase cable voltage measurement test platform, and the experimental results show that the three-phase measurement accuracy of the method proposed in this paper is less than 2% regardless of the three-phase voltage is balanced or unbalanced.