Pulmonary rehabilitation is consisted of breathing retraining, respiratory muscle rest, airway secretion elimination, reconditioning exercise, psychosocial support, nutritional support, adequate ventilator support, and patient education. And there are many techniques and devices to relieve and control the symptoms of respiratory diseases and to prevent from respiratory complications. Among them, the point of pulmonary rehabilitation is the non-invasive respiratory care by using respiratory muscle aids. All patients with impairment of pulmonary function can be differentiated into those who have primarily oxygenation impairment from predominantly intrinsic lung or obstructive diseases, and those with mechanical or restrictive lung disease on the basis of respiratory muscle dysfunction and ventilation impairment. The patients with primarily ventilatory impairment can benefit considerably from the use of both inspiratory and expiratory muscle aids. If we understand the pathophysiology of each pulmonary problem and evaluate the patient carefully and timely, we can minimize the respiratory complications through proper ventilatory and coughing support. Reduced respiratory complications can actually decrease the mortality rate. In conclusion, use of non-invasive respiratory aids, taking into account the characterization of respiratory pathophysiology, have made it possible to enhance quality of life as well as prolong the life span.