Abstract: Geomagnetic data of Antarctic region were used to study the characteristics of the disturbed daily variation (S D) of geomagnetic field. 1) Unlike S q field,S D field variation is irregular and doesn't have obvious differrence inthe daytime and nighttime. The S D variation is more intense in the solar maximum year(1991) than in the decreasing phase of solar cycle(1994) at Zhongshan Station. 2)Amplitude of the S D field at Zhongshan Station in polar cusp is ten times as large as that at Great Wall Station in sub auroral region and that at Beijing Observatory in low latitude of the north hemisphere. The S D field consist of the periodical disturbed daily variation (S 0 D) and superposed irregular intense disturbance (S d D). 3) The morphology of S 0 D(H) is a "Sin" pattern at Zhongshan Station,which is opposed to that at Great Wall Station and Beijing Observatory. 4) The equivalent current vectors of S 0 D variation at Zhongshan Station are clockwise westward in the morring afternoon (02-15h) and counter clockwise eastward in the afternoon-night(15-02h). Therefore,the S D field is cuased by the current system consisting of eastward and westward electroject current and the current vortex in the cap region at Zhongshan Station.The equivalent current vectors of S 0 D variation are very small at Great Wall Station and Beijing Observatory, so that S D field is affected by eastward and westward electroject current in the polar region.