基于现有地磁日变理论和改正方法,对国际公开地磁静日变数据进行傅里叶变换和一维连续小波变换综合分析,判断大于0.2 Hz频段为磁扰变化场在频域的体现,并利用一维离散小波变换将数据分离,完善了已有的地磁静日变改正方法.根据日变数据特征和一维离散小波分解特性,选定sym8小波作为基本小波对数据进行7层分解,将日变数据中长期变化和短期变化与磁扰部分在保证保真度条件下有效分离,并与傅里叶级数分解和低通滤波处理效果作对比验证,结果显示一维离散小波变换处理效果更佳.日变数据中短、长期变化与磁扰两部分数据的有效分离并分别改正可提高海洋地磁测量日变改正质量,降低海洋地磁数据处理过程中误差累积程度,提高了现行日变改正方法的科学性、准确性.“,”Based on the existing geomagnetic diurnal variation theory and correction method, this paper makes a comprehensive analysis of the international geomagnetic quiet diurnal variation by Fourier Transform and one-dimensional Continuous Wavelet Transform. The frequency band greater than 0.2 Hz is the embodiment of the geomagnetic disturbance field in the frequency domain. Discrete Wavelet Transform is used to separate the variation, thus improving accuracy of the existing geomagnetic diurnal variation correction method. According to the characteristics of variation and Discrete Wavelet Decomposition, Sym8 wavelet is selected as the basic wavelet to decompose the data at 7 layers. The long-term and short-term variation of geomagnetic diurnal variation are effectively separated from the geomagnetic disturbance part under the condition of ensuring the fidelity. Compared with the results of Fourier Series decomposition and low-pass filter, the processing effect of Discrete Wavelet Transform is better. The effective separation and correction of short-term, long-term variation and geomagnetic disturbances can improve the quality of diurnal variation correction in marine geomagnetic measurement, reduce the error accumulation in the process of marine geomagnetic data processing, and improve the scientificity and accuracy of the current diurnal variation correction methods.