Abstract: In order to provide backup navigation and positioning means when the GNSS cannot locate, it is an important direction to carry out research on non cooperative navigation and positioning related technologies based on very low frequency communication station signals. This paper proposes and verifies a phase measurement technology for very low frequency communication station signals, realizes phase measurement for very low frequency communication station signals, and uses two different measurement points, verified the accuracy of phase measurement. This method uses the characteristics of minimum shift keying (MSK) signal itself to calculate the relative phase of the receiving point, keep two test point at a certain distance, calculate the phase of the two receiving points, compare the distance difference calculated by the phase difference of the two test point with the distance difference between the two test point and the transmitting point, and verify the accuracy of this algorithm. By verifying that the method proposed in this article can accurately measure the phase difference between two receiving and transmitting points. This phase difference can reflect the distance difference, and navigation and positioning can be achieved by calculating the distance difference between multiple stations.