The purpose of aeromagnetic vector survey is to measure the three components of the magnetic field in aerogeophysical. The three-component magnetometer which is installed in the aircraft is used to measure the real-time information of the three-component magnetic field, at the same time, the inertial navigation equipment which is fixed together with the three-component magnetometer equipment is used to capture the real-time attitude data of the aircraft. The data collected by the inertial navigation system is based on the geographic coordinate system. And the data collected by the three-component magnetometer is based on the carrier coordinate system. The attitude coordinate transformation method is based on the correspondence between the geographic coordinate system and the vector coordinate system. This research is established to provide a theoretical basis for the aeromagnetic survey posture coordinate transformation. The correctness and validity of the attitude coordinate transformation method is verified by the simulated flight experiment.