With the purpose of the study on change rule of internal charge in soil specimens under differing circumstances, dredger fill, which was collected from Guangxi Beibu Gulf Economic Zone, was studied in various parameters, including the absence/presence of the applied DC electric field, different levels of field strength, soil water content, soil compactness, and degree of desalination. Moreover, through tentatively simulating the electrical response between thundercloud and earth mass, the triggered lightning mechanism of rock soil mass was explored. The results show that both additive electrical field and atmospheric electric field had influence over charge variation of soil, the impact of which would become more significant with the increasing field strength. Higher soil water content and lower degree of desalination could enhance the charge variation and conductivity of soil, whilst this action effect would remain stable when soil water content reached a certain degree. Although soil compactness make some effect for the charge distribution, its regularity is undefined so far.