The theoretical calculation method with formulae and the conventional measurement method of zero-sequence self-and mutual Mmpedance of high voltage cable lines are reviewed. Then the principles and mathematical models of zero-sequence parameter live-line measurement method of cable lines with mutual inductance based on GPS (Global Positioning System) technology are presented together with key techniques, hardware structure and software algorithm of the measurement system. Finally, field measurement results with the three different methods are given. Theoretical analysis and field measurement results prove that this new live-line method proposed in the paper is correct, effective and efficient.