Abstract: The existing electric field integral inversion method has limited field application conditions, and it is difficult to arrange electric field measurement points on high-span overhead lines. A non-intrusive voltage measurement method for overhead transmission lines based on the proximal electric field integration method is proposed, a single-phase overhead transmission line field source calculation model is established, the plumb line electric field distribution under the wire is analyzed, and the principle of the line proximal inversion method is introduced. COMSOL finite element simulation software is used to simulate the electric field distribution of the plumb line under 10 kV line. The proximal electric field coupling model of overhead transmission line is established to analyze the proximal three-phase electric field coupling crosstalk effect. Combined with the proximal integral inversion method, the numerical integral type, the integral node, the scale coefficient of the proximal integral region and remote auxiliary node are optimized. It is shown that whenk=0.9, the 3-point Gaussian-Chebyshev integral method can achieve accurate inversion calculation of three-phase voltage, and the maximum error of three-phase voltage is 2.55%. Furthermore, after introducing auxiliary nodes, the voltage inversion error is effectively reduced. Finally, a test platform for voltage inversion measurement of overhead lines is built, and MEMS electric field sensor is used to test the voltage inversion ability of 2 m high lines using 3-point Gaussian-Chebyshev integral method. Test inversion for voltage measurement error is 5.75%, the accuracy and feasibility of the proximal integral method are verified. The research results can provide theoretical guidance for non-intrusive voltage inversion measurements of overhead lines.