Secondary infiltrative tuberculosis means re-infection after previous infection with tuberculosis, where the main lesion is an infiltrative lesion associated with endogenous recurrence and exogenous re-infection. Secondary tuberculosis belongs to active tuberculosis, while infiltrative tuberculosis belongs to a kind of secondary tuberculosis, therefore, secondary infiltrative tuberculosis means the reappearance of tuberculosis lesions after previous infection with Mycobacterium tuberculosis, and the lesions are mainly infiltrative, which is considered to be a more serious condition compared with the previous one, and the foci have been gradually spreading, with inflammatory oozing, cellular infiltration, and so on. The causes of secondary infiltrative tuberculosis are mainly divided into endogenous recurrence and exogenous re-infection, the former refers to the re-activation of tubercle bacilli in the old primary foci, resulting in the rekindling of the foci; the latter refers to the development of tuberculosis after the primary infection is cured by the infection of tubercle bacilli from the outside world again. All in all, patients need to go to the hospital in time and cooperate with doctors for active treatment so as not to delay their condition.