The composite coatings of sodium alginate （SA） and konjac glucomannan （KGM） with different mass ratio were prepared by tape casting， and the physicochemical properties were measured. The preservation properties of the coatings on the ginger are researched. The results show that KGM makes the tensile strength and elongation at break of the SA coating increase significantly， and makes the water permeability and gas/ light permeability improve. Compared with the single SA coating， the SA/KGM composite coatings make the weight loss rate and respiration rate of the ginger decrease， the content decrease of total phenolics and flavonoids delay， the activity of PPO， POD and PAL restrain， the decrease of AsA， TA and the total soluble sugar content delay in the store process. So the qualities of the ginger are kept by the SA/KGM composite coatings. All KGM/SA composite coatings with different mass ratio can make the ginger keep fresh， and the preservation property of the KGM ∶ SA=2 ∶ 1 composite coating is the optimal.