Abstract: OBJECTIVE To explore the effect of tuberculosis infection T lymphocyte spot test combined with inflammatory indexes on diagnosis of tuberculosis of unknown origin. METHODS A total of 224 patients with tuberculosis of unknown origin who were treated in Chongqing Three Gorges Central Hospital from Oct 2014 to Jun 2017 were recruited as stud objects, the clinical data of all the patients were collected, and the related tests were performed. RESULTS Among the 224 patients with fever of unknown origin, there were 23 (10.27%) cases of active tuberculosis, 32 (14.29%) cases of viral infection, 122 (54.46%) cases of bacterial infection, 14 (6.25%) cases of neoplastic disease and 33 (14.73%) cases of autoimmune disease. There were significant differences in C-reactive protein, procalcitonin, ferritin, lactate dehydrogenase and erythrocyte sedimentation rate among the patients with fever of unknown origin who had different types of diseases (P＜0.05). The efficiency of the spot test combined with inflammatory indexes was higher than that of the single spot test or inflammatory indexes in diagnosis of active tuberculosis and bacterial infection, active tuberculosis and viral infection, active tuberculosis and tumor, and active tuberculosis and autoimmune disease. CONCLUSION The tuberculosis infection T lymphocyte spot test combined with inflammatory indexes may remarkably raise the specificity and sensitivity of diagnosis of tuberculosis in the patients with fever of unknown origin and facilitate the identification of type of disease by clinicians so as to take targeted treatment measures as early as possible.