Abstract: The accuracy of geomagnetic data acquisition directly affects the accuracy of geomagnetic matching and positioning. Geomagnetic diurnal variation correction is an important prerequisite for obtaining high-precision geomagnetic data. For example, it is relatively difficult to set up Geomagnetism Observation Base Station in the high seas and some remote areas which are far away from the effective range of stations, and ensuring the continuous and stable work of the Geomagnetism Observation Base Station puts forward higher requirements for the establishment. The steps of the correction of geomagnetic diurnal variation are complex and cumbersome, which are mostly realized by joint correction the geomagnetic diurnal variation of multiple stations or monitoring the change value of a station at the corresponding time. There are relatively few studies on geomagnetic diurnal variation correction in the process of regional measured geomagnetic data acquisition. To solve these problems, considering the characteristics of geomagnetic static diurnal variation with solar diurnal variation, the geomagnetic field variation law under multiple solar days at a single point and the geomagnetic field data at multiple points are fitted and corrected based on Gaussian fitting function. The experimental results show that the static diurnal variation of geomagnetic fitted by Gaussian function can meet the correction accuracy of geomagnetic diurnal variation in a certain region, and the fitting error is within a few nates, and the mean square error is no more than 10 nT. The correction value of geomagnetic diurnal variation fitted by Gaussian function in the region is compared with that obtained by conventional method, the difference of 82.3% is within ±5 nT. The geomagnetic diurnal variation correction analysis based on Gaussian function fitting can quickly obtain the estimation of the diurnal variation correction value according to the measurement time, realize geomagnetic diurnal variation correction, and obtain high-precision geomagnetic data, which provides the basis for geomagnetic matching and positioning.