The invention relates to traditional Chinese medicine compound Lianweng anti-dysenteric powder for treating white scour of piglet and a preparation method and application of the powder. The traditional Chinese medicine compound Lianweng anti-dysenteric powder is prepared from the following raw materials: 100g-300g of rhizoma coptidis, 100g-300g of radix pulsatillae, 200g of geranium wilfordii and 200g of rhubarb charcoal according to a scientific prescription and technology. The traditional Chinese medicine compound Lianweng anti-dysenteric powder is parapared by grinding the raw materials in an environment with a relatively low temperature and screening the ground raw materials with a 200-mesh sieve, thereby relieving the adverse effect of crude fibers and the like on the digestion function of piglets, and reducing the consumption of active ingredients to a certain degree. Since the particle size of the ground raw materials reaches around 75 microns, the active ingredients in the medicinal materials are sufficiently exposed, thus facilitating the digestion and absorption of the piglets, greatly improving the bioavailability of the medicine, saving traditional Chinese medicine resources, and improving the efficacy properly. When in use, the Lianweng anti-dysenteric powder is mixed with feed or mixed with water to drench the piglets; and the popularization and application of the Lianweng anti-dysenteric powder are facilitated due to the characteristic of convenience in use of the powder. The Lianweng anti-dysenteric powder disclosed by the invention realizes a relatively good therapeutical effect on the white scour of piglet caused by escherichia coli, and has good application and popularization prospect.