By analyzing the nutrient contents of cassava in its all growth stages from planting to harvest in Danzhou,Hainan Province,cassava's nutrition characteristic and its most suitable nutrition diagnosis part were studied.The results showed that:(1) The macro element contents of cassava varied with months and with organs,and their average contents in whole cassava plant presented K> N>Ca >Mg> P>S;(2) Leaves were identified as the diagnosis parts of nitrogen,phosphorus,potassium,magnesium and sulphur contents;(3) The ratio of average contents of nutrient elements in cassava plant was N:P:K:Ca:Mg:S=0.89~1.87:0.14~0.27:1.06~1.72:0.54~0.99:0.18~0.32:0.06~0.16;(4) During the stage of reproduction,the contents of N,P,K,Ca,Mg and S of cassava dropped with the increasing of plant age regularly.