The paper deals with the morphological structure and histology of larynx, trachea and lung of Dugong dugon.

Larynx of Dugong dugon looks like a head of the goose. Laryngeal beak is short and coarse, bell is located on the top of the base of laryngeal beak. There are eleven cartilagines laryngis, which are a pairs of dissociative epiglottises, a pairs of healed arytenoid in the base, a cake of cricoid cartilage and three pairs of corniculate cartilages. And these cartilages are connected by a tough connective tissue. There are no vocal cords in the larynx; false vocal cords, however, exist at the bottom of the laryngeal room, but have lost the function to the sound.

The trachea of Dugong dugon is short and coarse, and the trachea is divided into right and left truncus bronchial magistralis, which look much longer. Therefore, there are only two trunks of arbor bronchialis distributed evenly within the lung. The epithelia of bronchi are pseudostratified columnar ciliate epithelia. There are goblet cells in the epithelia of the bronchi.

The lung of Dugong dugon is divided into more long two lobes, but lobule of the lung does not exist. There is the criss-cross muscle fiber in tissue of the lung. The end of the respiratory bronchiole exist sphincter. Cartilaginous bones are existed within wall of alveolar duct. Dense capillaries are distributed on the two sides of alveolar septum.