Objective To investigate the clinical characteristics,diagnosis, treatment and prognosis of intrathoracic sarcoidosis. Methods The clinical data of 55 patients with intrathoracic sarcoidosis were collected, and the clinical characteristics, treatment process and prognosis were retrospectively analysed. Results Among the 55 patients, females were more than males, and patients aged between 51 and 60 years accounted for the majority. There was no specific manifestation, and cough was the most common symptom, while some patients were free from symptoms. Thirty-nine patients received treatment with glucocorticoids. Four of the 39 patients aggravated during tapering of glucocorticoids, and got better after treatment with a larger dose and tapering moderately. One of the 39 patients relapsed 4 years after glucocorticoids withdrawl, and no longer relapsed for 6 years after a second treatment with glucocorticoids. The adverse effects in patients treated with glucocorticoids were obesity, peptic ulcer and osteoporosis, while no life-threatening complications occurred. Conclusion The main clinical manifestation of intrathoracic sarcoidosis is cough, and the adverse effects should be intensively monitored for the long-term use of glucocorticoids.