The results of mobile geomagnetic data processing may contain significant trend components, which interfere with the identification of anomalous information, and their removal thus becomes necessary. In this paper, the trend surface analysis method was applied to determine and strip the trend components from mobile geomagnetic data processing results. The results showed that the trend surface analysis method could effectively determine and remove the regional variation components of the lithosphere magnetic field in the monitoring area, and make the spatial distribution of the local anomalous components clearer and more reasonable. This is helpful for the identification of precursory anomalies. The technological ideas adopted in this paper are innovative, and the process of technological treatment is relatively simple, operable, and clear in its physical significance.