Abstract: In order to study the natural contamination depositing law of line disc anti-contamination glass insulator,experiments have been conducted for two years in Guangzhou.This article analyzed the seasonal character,the correlation character,the contamination depositing uneven character and the ratio between soluble deposit density（NSDD） and equivalent salt deposit density（ESDD） based on the experimental data.The information of the four characters was described,and the reason of their performance was explained.Finally,it was found that these characters are mainly caused by the different rain washing effects between upper surface and lower surface,ESDD and NSDD;and the natural contamination depositing situation in dry season.