A high-accuracy geomagnetic vector measurement method is characterized in that a vertical additional 
magnetic field and a horizontal additional 
magnetic field which have the same intensity but different directions are added to the position of a probe of a high-accuracy total-field 
magnetometer; a geomagnetic field without additional magnetic fields and a 
resultant magnetic field with an additional forward magnetic field and an additional reversed magnetic field are measured respectively; and then, each component, including a vertical component Z, a horizontal component H, a geomagnetic inclination I and a 
declination D, of a geomagnetic vector can be computed, and the method is suitable for fast and high-accuracy geomagnetic vector measurement outdoors or in a fixed 
station. According to the method, the geomagnetic vector measuring accuracy is in 
positive correlation with the accuracy of the matched 
magnetometer, and the high-accuracy total-field 
magnetometer is superior to a fluxgate three-component magnetometer with 10 nT of measuring errors. A high-accuracy geomagnetic 
vector field measurement device comprises one group or two groups of field coils and a tripod, the field coils are added to the outside of the high-accuracy total-field magnetometer probe, and the field 
measurement device is matched with the high-accuracy total-field magnetometer and used for rapidly measuring each component of the geomagnetic vector outdoors or in the fixed 
station.