Tracheobronchial injury following blunt chest trauma is a rare but potentially lethal injury. Often the diagnosis and treatment are delayed, resulting in attempted surgical repair months or even years after the injury. We described the case of a patient with post-traumatic left main bronchus stenosis. Before the diagnosis, the patient, with left lung white-out, was subjected to a tube thoracostomy, resulting in splenic penetration. Thus, the importance of a "safe triangle" and ultrasound guidance are emphasized for chest drainage. The late injury presenting as a stenosis was successfully managed by sleeve resection and reconstruction of the left main bronchus.