本文根据海洋磁力测量的资料提供了地球磁场年平均变化的确定方法。并对所获得的成果进行了评价。在大洋水域中确定地磁场的长期变化自然具有一定的特殊性。因而,就有必要产生对海洋磁力测量资料进行整理的方法和依据。根据这些资料,在确定长期变化时,其基本特性之一是在海洋中确定船位造成的误差很大。所以,作为两条航线的“交叉点”势必通过某一地区,而该地区的范围是由连测误差所确定的。在异常场中,这些因素会导致出现长期变化的 This paper provides a method to determine the average annual change of the Earth’s magnetic field based on the ocean magnetic force measurements. The results obtained were evaluated. In the ocean waters to determine the long-term changes in geomagnetic field has its own particularity. Therefore, it is necessary to produce a method and basis for finishing marine magnetic survey data. According to these sources, one of the basic characteristics in determining long-term changes is the large error caused by determining the ship’s position in the oceans. Therefore, the “intersection” as the two routes will inevitably pass through a certain area, and the area is determined by the continuous measurement error. In abnormal fields, these factors can lead to long-term changes