The invention provides a traditional Chinese medicine composition for treating mycoplasmal pneumonia of swine and a preparation method thereof. The composition is made from the following materials: 5-12 parts of balloonflower root, 5-12 parts of white swallowwort, 5-12 parts of radix asteris, 5-12 parts of white mulberry bark, 3-8 parts of birthwort fruit, 3-8 parts of tuber stemona root, 3-8 parts of perilla fruit, 5-12 parts of scutellaria root, 3-8 parts of apricot kernel, 3-8 parts of wind-weed rhizome, 3-8 parts of red sage root, 3-8 parts of angelica, 3-8 parts of zedoary, 1-7 parts of dried tangerine peel and 1-5 parts of licorice. The preparation method comprises the following steps: proportionally adding water to the traditional Chinese medicines for soaking, decocting for three times, taking filtrate, keeping standing, condensing to relative density of 1.0-1.2, and obtaining the traditional Chinese medicine composition. The traditional Chinese medicine composition is of low toxicity, can effectively treat mycoplasmal pneumonia of swine, enhance adversity resistance ability of the body at the same time, has simple preparation method, and is suitable for the needs of large-scale industrial production.