Abstract: A field experiment was carried out to investigate the effects of magnesium nutrition on yield, quality and nutrition content of winter potato tuber. The result showed that the yield increased and the crude protein, soluble sugar and starch content of potato tuber enhanced, and the nitrogen, potassium and magnesium content of potato tuber increased when magnesium fertilizer was applied. It is suggested that 75.0 kg/hm2 application on winter potato in Pearl River Delta area is advisable.