The invention provides a traditional Chinese medicine for treating an attention deficit hyperactivity disorder and a preparation method thereof. The traditional Chinese medicine is prepared from Nepal rattlesnake plantain roots, Chinese tupistra rhizomes, seeds of ragimillet, dwarf cowlily rhizomes, false-yellowflower milkwort roots or herb, peel of roseapple, giantreed rhizomes, stem leaves or roots of ipomoea cairica (L.) sweet, eastern bracken fern rhizomes, all-grass of filifolium sibiricum (L.) Kitam., acute sida leaves or roots, herb of Japanese phtheirospermum, smallflower seaberry herb, tuber fern, all-grass of aeschynanthus acuminatus Wall., longtube ground ivy herb, common melastoma herb, root of seven-sisters Japanese rose, false Chinese swertia herb, ellpticleaf spurgentian roots, Tonkin tinomiscium stems and henry biondia herb with roots. The traditional Chinese medicine for treating the attention deficit hyperactivity disorder and the preparation method thereof have the advantages that the traditional Chinese medicine can be combined with conventional western medicines (e.g. tomoxetine) for treating the attention deficit hyperactivity disorder, use is safe and convenient, the treatment effect is better, no toxic or side effect exists, the adverse reactions of the western medicines are reduced, and the preparation process is simple.