Ship degaussing is one of the important means to effectively protect ship from mine attack. Efficient and accurate magnetic measurement technology is the premise of ship degaussing. Aiming at the position difference problem of the measuring points between the portable magnetometer and the large plane magnetometer array used in the first degaussing work of ship，the underwater magnetic field conversion method of the ship based on the magnetic dipole array is proposed. The standardized database of the ship geometric model is introduced to calculate the magnetic field at the underwater standard measuring points of the ship，which solves the practical problem that the position difference of the measuring points makes it impossible to give full play to the automatic large-plane magnetometer of the degaussing station. This method is suitable for most ship degaussing stations.
