The invention discloses a traditional Chinese medicine composition for treating cancer pain and ascites, which comprises: Baiwei, Sophora flavescens, Angelica sinensis, Sanleng, Curcuma, Rhubarb, Ishijianchuan, Bombyx mori, Honeycomb and Aescin. The invention also discloses a traditional Chinese medicine plaster for treating cancer pain and ascites and a preparation method thereof. The traditional Chinese medicine plaster contains glycerin, NP-700, PVP K-90, EDTA-2Na, Chinese medicinal extract, azone, and the mass ratio It is 11:5:0.7:0.1:8:0.9. The traditional Chinese medicine composition of the present invention has the effects of clearing away heat and detoxification, promoting blood circulation and removing blood stasis, reducing swelling and relieving pain, and can be used for treating benign or malignant tumors of the lung, liver, breast, thyroid and other benign or malignant tumors and nameless swelling. Using the sticking therapy of tumor external treatment, the medicine is reconciled and applied to the affected area to exert a direct anti-tumor effect, and effectively control the cancer pain and complications of malignant tumors such as malignant pleural effusion, significantly improve the patient's symptoms, relieve suffering of patients.