The alveolar bone remodeling is essential in tooth movement by orthodontic forces. The collagen and chondroitin sulfate are acting as an important roles in bone remodeling. This study was performed to measure out the quantity of the collagen and chondroitin sulfate in the alveolar bone of rats applied by experimental orthodontic forces. The 150 Sprague-Dawley male rats were divided into the PGE_² treated group, indomethacin treated group and the normal group. A 80gm force rubber band was used as a orthodontic appliance between upper incisors and right upper 1st molar, and left side of experimental rats with no appliance was regarded as a control side. The samples of alveolar bones were obtained from pressure and tension sites in all three groups. respectively, and in control sides, too. The results were as follows. 1. The change in total collagen remains stable in both pressure and tension sites of all three groups, compared with control side by the time consuming. 2. The change in soluble collagen showed the most highest level in tension site, lowest level in pressure site of PGE_² treated group in 5th. experimental day. 3. The change in chondroitin sulfate showed the most highest level in pressure site, lowest level in tension site of PGE_² treated group in 5th. experimental day. 4. In indomethacin treated group, the change of soluble collagen and chondroitin sulfate showed small range of variance compared with PGE_² treated and normal group.