We propose a novel contactless measurement technique for detecting the phasing of double overhead transmission lines which are used to supply power to a transformer in the substation. Different from traditional contactless methods whose sensors should be quite close to measured overhead lines, the proposed method uses a electric field (EF) sensor located on the ground to measure the ground-level electric field distribution. Then, the remote contactless phasing test method can be realized based on the distribution waveform. The proposed method has been validated by experimental tests on a reduced scale model of double overhead transmission lines.