Abstract: OBJECTIVE To investigate the curative effect and imaging evaluation of increasing dose and prolonging the intensive phase in the retreated pulmonary tuberculosis patients with positive bacteria. METHODS Ninety cases of non-resistant bacterial positive pulmonary tuberculosis patients who were treated in Ningbo Second Hospital from January 2015 to June 2016 were collected. All patients were randomly divided into control group (45 cases) and experimental group (45 cases). The control group was given standard 2HRZES/6HRE. The experimental group was given high dose isoniazid and rifampin and 3 months intensive phase. The sputum smear negative conversion rate, clinical and imaging efficacy, adverse reaction rate and the recurrence rate after completion of treatment were compared between 2 groups. RESULTS The effective rates in focus of control group and experimental group were 75.55% and 91.11% respectively (P<0.05). The success rates of treatment in the control group and experimental group were 71.11% and 88.89%, and the cure rates were 48.89% and 71.11%, respectively (P<0.05). The sputum smears negative conversion rates of the control group and the experimental group in the first 20 weeks were 68.89% and 84.44% respectively. The median negative conversion time of the experimental group was 8 weeks, which was significantly lower than that of the control group (14 weeks) (P<0.05). The recurrence rates in control group and experimental group within 24 weeks after treatment were 18.75% and 5.00% respectively. The recurrence risk in experimental group was significantly lower than that in control group (P<0.05). There was no significant difference in adverse reaction rates between 2 groups. CONCLUSION It has high clinical efficacy and safety in increasing the dose and prolonging the intensive phase in the treatment of patients with pulmonary tuberculosis, can significantly shorten the time of sputum smear negative conversion and obviously reduce the recurrence risk after treatment.