The invention discloses a calculation method of slope cracking caused by taproot-system arbores under a typhoon effect. The method is characterized in that the taproot-system arbores are generalized into rod models buried in soil, and the width and depth of the slope cracking are determined by calculating the horizontal displacement of rods at optional depths. The method specially includes the steps of A, determining the shape parameters, which include height, crown height and crown widths, of trees; B, calculating the bending moment and shearing force of overground trunks; C, generalizing the taproot-system arbores into the rod models buried in soil, and calculating the displacement and rotation angles of the overground rods; D, calculating the horizontal displacement of the rods at optional depths to obtain the width and depth of the slope cracking caused by the taproot-system arbores under the typhoon effect. The calculation method has the advantages that the conditions of the slope cracking caused by the effects of typhoons of different wind scales are determined, a basis is provided for the typhoon storm seepage calculation, and accordingly the evaluation of a typhoon storm type slope is practical; the method is quite practical.