In view of the existence of the model-induced semantic conflict and inconsistency in the common information model（CIM）information exchange and application integration，it is necessary to quickly and accurately identify the differences between models，but manual analysis is time-consuming.To solve this problem，a research method of CIM update and extension based on ontology is proposed.The CIM update and extension are divided into four scenarios，add，delete，change and rename，with all the corresponding algorithms described.Finally，through a comparison of experimental results of the model for an actual project with those of manual search，it is verified that the method proposed is effective and practical.