Objective To analyze the CT features of bacterial positive cavitary pulmonary tuberculosis in the elderly and young patients in order to improve the understanding of the disease in the elderly. Methods Clinical data of 42 elderly patients (≥60 years old, elderly group) and 45 young patients (<45 years old, youth group) with cavitary pulmonary tuberculosis identified with sputum culture and pathological results in our hospital from January 2017 to January 2021 were collected and analyzed retrospectively. The CT imaging signs were compared between the 2 groups. SPSS statistics 22.0 was used for data analysis. According to the data type, Chi-square test was employed for comparison between groups. Results The elderly group had significantly larger proportions of lesions involving the whole lung lobe, presence of insect phagocytic cavities, small nodules, consolidation or atelectasis, pulmonary calcification, pleural effusion, mediastinal lymphadenopathy and hilar lymphadenopathy when compared with the youth group [78.6% (33/42) vs 31.1% (14/45), 42.9% (18/42) vs 20.0% (9/45), 95.2% (40/42) vs 80.0% (36/45), 47.6% (20/42) vs 24.4% (11/45), 57.1% (24/42) vs 13.3% (6/45), 33.3% (14/42) vs 13.3% (6/45), 40.5% (17/42) vs 15.6% (7/45), 28.6% (12/42) vs 2.2% (1/45); all P<0.05]. There were obviously rarer tree bud sign and millet shadow in the elderly group than the youth group [47.6% (20/42) vs 80.0% (36/45), 2.4% (1/42) vs 17.8% (8/45); both P＜0.05]. Conclusion The CT findings of senile cavitary pulmonary tuberculosis have certain characteristics, which play a positive guiding role in clinical treatment, prognosis evaluation and prevention of drug resistance.