Abstract: For investigating the protective effect of compound traditional Chinese medicine in preventing mycoplasmal pneumonia and the feasibility of substituting TCM for tiamutin as the drug for preventing mycoplasmal pneumonia. In this paper, we selected the compound TCM and Tiamutin were selected as the drug for preventing mycoplasmal pneumonia which respectively added to pit diets according to the proportion respectively. In TCM group, the incidence for 4 month were 16.67%, 10%, 6.67%, 3.33%. And the incidence for tiamutin group were 13.33%, 10%, 20%, 26.67%. The experimental results show that, by using compound TCM to prevent and treat mycoplasma pneumonia of swine, can significantly reduce the incidence rate of mycoplasmal pneumonia of swine, relative to the Tianmutin group, with the passage of time, the control effect of compound TCM has been maintained, and control effect of Tiamutin group was getting worse. Therefore, the compound traditional Chinese medicine can replace of tiamutin to prevention and treatment of mycoplasmal pneumonia of swine. It shows that the first prescriptions works the best.

Key words: Mycoplasmal Pneumonia of Swine, compound TCM, tiamutin