A localization device using a magnetic field for positioning a moving object is provided. The localization device includes a magnetic landmark, a set of at least four tri-axes magnetic sensors mounted on the moving object, and a logic operation processing unit. The set of at least four tri-axes magnetic sensors forms four non-coplanar points in a three-dimension coordinate system. The logic operation processing unit is connected to the set of at least four tri-axes magnetic sensors. The set of at least four tri-axes magnetic sensors senses the magnetic field of the magnetic landmark and generates at least four magnetic signals transmitted to the logic operation processing unit.