The invention provides a traditional Chinese medicine for treating arrhythmia due to heart-spleen deficiency and a preparation method thereof. The traditional Chinese medicine for treating the arrhythmia due to heart-spleen deficiency is prepared from the following raw materials: stropanthus divericatus, lycoris, coriaceous knotweed rhizome, celery, wilson begonia rhizome, fragrant sarcococca herb, sambucus adnata wall, mimosa pudica, corallodiscus flabellate, cinnabar, hairyvein agrimony, grass, orchidaceae ludisia, dioscorea pentaphylla, companumoea root, panicled fameflower root, dillseed, madder root and humulus lupulus. The traditional Chinese medicine for treating the arrhythmia due to heart-spleen deficiency has the beneficial effects that the theory of traditional Chinese medicines is utilized, and the advantages of quick effect, definite therapeutic effect, high safety, no toxic or side effect and difficulty in recurrence can be realized when the traditional Chinese medicine provided by the invention is used for treating the arrhythmia due to heart-spleen deficiency.