The invention discloses a traditional Chinese medicinal psoralen-containing composition for treating stomach cancer and a preparation method and an application thereof. The traditional Chinese medicinal composition comprises the following components: by weight, 50%-96.77% of roud cardamon seed volatile oil, and 3.23%-50% of psoralen. The invention also discloses a preparation method of the traditional Chinese medicinal psoralen-containing composition. The invention also discloses an application of the traditional Chinese medicinal psoralen-containing composition in the preparation of a medicine against stomach cancer as well as a medicine for inhibiting tumor cells. Combination of psoralen and roud cardamon seed volatile oil has a tumor-inhibitory synergism. When the weight ratio of psoralen to roud cardamon seed volatile oil is 1:30, the prepared traditional Chinese medicinal psoralen-containing composition can remarkably inhibit growth of tumors in mice. Analyzing from theory of traditional Chinese medicine, as roud cardamon seed is a medicine for resolving damp with aromatics, roud cardamon seed can assist efficacy of the mild drug Psoralea corylifolia when fragrance of roud cardamon seed overflows all around. With the compatibility of the two drugs, the good effect of treating tumor is achieved.