Obstructive sialadenitis of major salivary glands is a common entity that occurs either in sialolithiasis or in foreign-body obstruction of the excretory ducts. This is characterized histologically by the presence of duct-like structural groups in a highly fibrotic stroma. Although the pathologic features are well recognized, the various cell types involved in the atrophy and subsequent regeneration of the obstructed salivary gland have been controversial. For this reason, an animal model of obstructive sialadenitis that induced atrophy in the salivary gland was used. Experimental study was performed to observe changes of submandibular gland in rabbit and apply the results to clinical activity. Forty-five rabbits each weighing about 3Kg were used and divided into control and experimental group. In the experimental group, ducts of submandibular gland was ligated and cutted divided into each twenty rabbits. Rabbits were serially sacrificed on the 3rd, 5th, 14th, 30th day of experiment. The submandibular glands were dissected out at sacrifice and stained with H&E, MT, immunohistochemical stain and the histological examinations were carried out under the light and transmission electron microscope. After examination and comparison of all specimens, the results of this study were as follows: 1. In the features of H&E stain, moderate infiltration of inflammatory cell were present at 3rd day of experiment. The features of ductal metaplasia was observed after 7th day in the ligation group and destructive changes was continued. In the cutting group, atrophic changes were less severe than ligation group but the small ductule were separated from stroma after 7th day. 2. In the feature of MT stain, apposition of connective tissue was increased in all group, more active in ligation group. 3. In the features of immunohistochemical stain, ligation group showed increased PCNA positive response at 7th day and the higher activity of duct cells was observed. Severance group showed more PCNA positive response than ligation group at 30th day. 4. In TEM features, ductal metaplasia was started at 7th day and degenerative change with margination of nucleus had been severe. Although ductal metaplasia was seen in the severance group, more numerous granule in different size was founded than ligation group. From above results, degenerative change was identified with ductal metaplasia, apically apposition of granule, r-ER destruction in ligation group. Severance of duct elicit degenerative change of grandular cells but the change was less severe than ligation group and more PCNA positive cell was founded at acinar cell.