In this study, after comparing of three formulas that they are Abbott formula, Henderson\|Tilton formula and Yang xindong formula for calculating of outbreak control multi\|cycle plant disease, there is the result: Yang xindong formula is the optimization. In Abbott formula, the more the radio of the initial epidemic situation in treatment and control is, the greater error is; The smaller the values of the initial epidemic situation in treatment and control are, the greater error is. The greater the values of final epidemic situation in treatment and control are, the greater error is obviously. In Henderson\|Tilton formula, the smaller the radio of the initial epidemic situation in treatment and control is, the greater error is. The greater the values of the initial epidemic situation in treatment and control are, the greater error is. The greater the values of final epidemic situation in treatment and control are, the greater error is obviously. When the initial epidemic situations in treatment and in control are great disparity, or the final epidemic situations in treatment and in control are greater than 05 even, the control effect can’t be evaluate with Abbott formula and Henderson\|Tilton formula but Yang xindong formula.