Abstract: Objective To study on the reason of affecting the smear negative result at the end of 2^nd month of treatment of new smear positive pulmonary tuberculosis patients of tuberculosis control,so as to improve the treatment for the new smear positive pulmonary tuberculosis patients.Methods Based on the patient’s phlegm bacterium volume,focus scope,with or without cavities in lungs and whether have other complication(e.g diabetes and drug resistance situation,analysis the influence factors on the smear negative result at the end of 2^nd month of treatment on the new smear positive pulmonary tuberculosis patients. Results When phlegm bacterium volume are in the level of 3 times smear positive,2 times smear positive;one time smear positive and smear negative pei+,the clearance rate are 66.7%、81.2%、92.5% and 95.7% at the end of 2^nd month treatment respectively.Within 3 time smear positive,when phlegm bacterium volume of the specimen are in the level of 4+、3+、2+、1+,the clearance rate are 51.0%、60.5%、66.2% and 81.2% respectively.Clearance rate at the 2^nd month treatment of single drug resistance is 87.2%.Clearance rate at the 2^nd month treatment of two drugs resistance,three drugs resistance and four drugs resistance are 82.8%,74.3% and 70.6% respectively.Clearance rate at the 2^nd month treatment of multi drug resistance is 73.3%.When focus scope within 16 pulmonary field,the clearance rate are 93.6%,88.7%,77.9% 65.1%, 62.4% and 68% respectively.Those cases without cavities the clearance rate at the end of 2^nd month of the treatment can reach 87.6%.Single cavities cases the clearance rate can reach 77.4%.The multi cavities cases the clearance rate is only 47.6%.In the case of pulmonary,the clearance rate is 83.3% at the end of 2^nd month of the treatment,while pulmonary combined with diabetes the clearance rate is only 63.5%.We perform regression analysis on the above mentioned affecting factors,there is statistic meaning on the difference（smear negative and non-smear negative group） of variables of the patient’s phlegm bacterium volume,drug resistance situation,with or without cavities in lungs and whether have other complication（e.g diabetes）.The above mentioned 4 factors are independent reasons of affecting smear negative result at the end of 2^nd month.Conclusions Patient’s phlegm bacterium volume,drug resistance situation,with or without cavities in lungs and whether have other complication（e.g diabetes） are all the factors to affect the clearance result at the end of 2^nd month of treatment on the new smear positive pulmonary tuberculosis patients.It is also important to improve the register control on the new smear positive pulmonary tuberculosis patients,the health education need to be enhanced on the tuberculosis control,define the correct timing for the phlegm checking s also a important measure to improve the clearance rate at the end of 2^nd month of the treatment.

Key words: Pulmonary tuberculosis/prevention and control