Lung cancer coughing sputum with white foam is mainly caused by the stimulation of surrounding bronchial tubes by the lesion, which leads to excessive secretion of white mucus-like liquid from its mucosa. Early stage of lung cancer mainly manifests as paroxysmal irritating dry cough, which is related to the stimulation of mucous membrane in the trachea by the tumor. With the development of the disease, the tumor continues to grow, which can press and stimulate the adjacent trachea mucous membrane, or when the tumor cells directly invade and stimulate the trachea mucous membrane, it can cause the mucous membrane to promote the secretion of a large amount of white mucus-like liquid. These mucus and the foam produced will be gradually discharged from the body with the patient’s cough, manifesting the symptom of coughing up sputum with white foam. Once diagnosed, lung cancer patients should actively cooperate with treatment, early detection and early treatment, so as not to delay the condition.