Provided is a database schema migration difference detecting technique for detecting differences of a customized database schema before and after database migration by using XML technology, including: extracting a first database schema from a fresh database of a release and saving the first database schema in a first XML file; extracting a customized database schema from a customized database of the release and saving the customized database schema in a second XML file; comparing the first and second XML files, filtering the identical content in the first and second XML files and saving differences in a delta XML file; and comparing the delta XML file with a new database to detect a state of the customized database schema after migration. The detecting state indicates whether there is any loss or change in the customized database schema after migration, as well as, conflicts with the database schema in a database of a new release.