Abstract: Objective To establish a new method and calculat ing formula for estimation the prevalence of smear positive tuberculosis. Methods To use the parameter of the smear positive tuberculosis patients between patients who with suspect sympotoms and who without suspect sympotoms for establishing the new estimation method.Results (1)The proportions of the smear positive tuberculosis patients who with suspectsy mpotoms and without suspect sympotoms was 75% and 25% respectively in the 4th TB survey. The formula was established by parameter is:R=Sn×(1+1/3)/N,R is preval ence of smear positive tuberculosis; Sn is the number of smear positive tubercul osis patients who with suspect sympotoms detected in a survey that just focus on TB suspects or screening and examination；N is the number of TB suspects examin ed in the survey.(2)The cost of the survey is lower than routine method. Conclusion The new method is a scientific, simple and convenient, low cost. The method and formula can be used for survey of prevalence of sputum smear positive pulmonary tuberculosis.

Key words: Pulmonary tuberculosis/epidemiology, Epidemiologica l method