The systematic optimization of applying fertilizer technique in sugarcane was studiedby the best modeling approach according to the principle of systematic engineering.A set of combining apply fertilizer method accorded with the systhentic targetsincluding the yields of high, medium and low, net profit and Sucrose content of canewas worked out by the systematic optimization of the best modeling approach usingcomputer. Other results were also discussed.The results provided the method and the-ory of reasonable applying fertilizer in sugarcane production.