Objective: To study the effects of Nd:YAG laser irradiation on the canine tooth pulps. Methods: The crown pulp of dog was exposed and excised by ND:YAG laser irradiation. Histopathological examination was used to check changes of the tissues in root canal and periodontium. Results: The pulp of the crown could be successfully excised by Nd:YAG laser without harmful changes in either root canal or periodontal tissues. Conclusion: This study may provide an experimental basis for the clinical possibility of crown pulp excision by using Nd:YAG laser irradiation.