In order to explore the influence of calcium and magnesium deficiency on growth and mineral elements absorption of different sweetpotato varieties,the method of sand culture was adopted.The symptoms appearance,chlorophyll content,photosynthesis,the ground and underground biomass,root and leaf mineral element content of Su16 and Su11 were studied under the condition of calcium and magnesium deficiency.The results showed that chlorophyll content,net photosynthetic rate,the ground and underground biomass of Su16 and Su11 were decreased significantly under calcium and magnesium deficiency,but Su11 declined more than Su16.Moreover,under the condition of calcium deficiency,Su16 appeared typical symptoms of rotten root,and the calcium content of Su16 in root and leaf decreased significantly(P<0.05),while Su11 appeared typical symptoms that necrotic patches in old leaves near petiole spread irregularly beyond the leaf edge,then gradually withered and fell.The calcium content of Su11 in root decreased significantly with iron content decreasing significantly(P<0.05).It was suggesting that calcium deficiency might be associated with iron deficiency.Under magnesium deficiency condition,typical symptom of Su16 and Su11 was the same,for both of them the leaves became yellow and the old leaves fell and withered gradually.Under magnesium deficiency,the magnesium content of roots and leaves decreased significantly with sulfur content decreasing significantly(P<0.05).It was suggesting that magnesium deficiency might be associated with sulfur deficiency.