Objective To evaluate the clinical value of contrast-enhanced ultrasonography (CEUS) in the diagnosis of central lung cancer with obstructive atelectasis. Methods During the period from July 2015 to October 2017, 36 central lung cancer patients with atelectasis were admitted to the First People's Hospital of Hangzhou. All the patients were diagnosed by clinical pathology, and the lesions can be demonstrated by ultrasound. CEUS was performed on all the patients. After the examination, the time from which central lung cancer began to increase, the time at which the lungs began to inflate, and the peak and disappearance time of both were analyzed, and the enhancement pattern of the lesions were observed. Results CEUS clearly distinguished central lung cancer and atelectasis in all the 36 (100%) patients. CEUS showed central lung cancer as ″slow-in and fast-out″ mode in 32 of 36 patients, and as ″fast-out and fast-in″mode in the remaining four cases. Among all patients, 18 had uniform low enhancement, 12 had non-uniform low enhancement, 4 had uniform high enhancement, and 2 had non-uniform high enhancement. The onset enhancement time was 4-10 seconds in 32 patients, and 10-18 seconds in 4 cases. The onset enhancement time of the tumor tissue was 10-15 seconds. Conclusion CEUS can distinguish tumor tissue from atelectasis and is helpful in discovering tumor tissue hidden in atelectasis.