Electric field mills play an important role in measuring near-ground electric field,whose observation accuracy is prone to be influenced by many factors.Based on experiments with upright and inverted probes,this paper demonstrates that the orientationouts of the probes makes no difference to the results,while inverted probes couldminimize impacts of charged raindrops in the perennial and all-weather observation.In addition,it puts up a calibration method to get the electric field value on the ground in different weathers and different amplitudes of atmospheric electric field,which can eliminate impacts of the surroundings to realize uniformity and comparability of data from multiple sites.