1) Re-cxpansion of the lung, a condition occupying the thoracic cavity with remaining lung. was related to over-expansion and displacement of the lung itself, and to reduction of thoracic cavity dne to displacement of the diaphraem and the mediastinum. The main roles in over-expansion and displacement of the lung were played by apical segment and S4 and S5 of middle lobe. 2) The result in re-cxpansion was better in the younger than the older, the female than the female than the male. 3) Intensity of thickening and adhesion of the pleura were intimately related to the re-expansion, worse in intense adhesion and addition of extrapleural decortication. No relations were observed between re-expansion and separation of diaphragmatic pleura. 4) The expansion was less when the resecting area was larger, and in the cases resected apical segment as compared with the other portion. 5) Re-expansion was worse in the cases in which hemorrhage during aed after operation was severe. 6) Re-expansion was much better in the cases presented a slight stenosis of bronchus.