Abstract In order to analyze the local geomagnetic field model according to the potential theory, based on studying and analyzing the theories and method of rectangular harmonic analysis (RHA) for building local geomagnetic model, several key problems, such as quality control of geomagnetic data, the representness and resolution of data, the choice of truncation order of geomagnetic model and boundary effect and its elimination, are discussed. At the same time, a kind of idea for building model by subarea is presented and applied to an actual China marine region. The new method is compared with the method of spherical cap harmonic analaysis (SCHA) and Talyor ploynimial method. A conclusion is that RHA has high accuracy in building local marine geomagnetical model.
