Objective To investigate the characteristics and signs of 18F-FDG PET/CT imaging in extrapulmonary tuberculosis, so as to improve the understanding and diagnosis level of extrapulmonary tuberculosis. Methods The 18F-FDG PET/CT data of 23 patients with extrapulmonary tuberculosis diagnosed by pathology and laboratory examinations were retrospectively analyzed. The SUVmax of the active lesion was measured with the results subject to the semi-quantitative analysis. Results There were a total of 41 lesions in 23 patients with extrapulmonary tuberculosis, 13 patients with multiple extrapulmonary tuberculosis. Except for one site of liver tuberculosis and one site of intracranial tuberculosis, the rest showed varying degrees of the increase in 18F-FDG metabolism, SUVmax2.9-28.3. According to the pathogenesis site, extrapulmonary tuberculosis was roughly divided into four types: (1) lymph node tuberculosis, mainly characterized by lymph nodes in varying degrees of swelling of which some were with calcification. (2) serous tuberculosis, including pleura and peritoneal tuberculosis, mainly characterized by the diffuse thickening (as a main phenomenon), some nodular thickening. (3) bone tuberculosis, characterized by osteolytic bone destruction, some with intervertebral disc involvement and paraspinal abscess formation, (4) organ tuberculosis (liver and spleen tuberculosis was found with soft tissue nodules and masses; ureteral tuberculosis with wall thickening and secondary hydronephrosis, annex tuberculosis was mainly characterized by soft tissue thickening, tubal tortuous thickening, ileocecal tuberculosis was characterized by intestinal wall ring-shaped thickening, narrowing of intestinal cavity, intracranial tuberculosis was characterized by multiple intracranial nodules with peripheral edema. There was one patient with concurrent soft tissue mass in the right side of the buttock. Conclusion 18F-FDG PET/CT imaging is helpful to show the location, morphology and metabolic characteristics of pulmonary tuberculosis, which is of great clinical value in the early diagnosis and differential diagnosis of extrapulmonary tuberculosis.