Multiplexing output consistency is an important technical indicators for current transformer verification device. Based on current transformer error experiment theories, Testing program is introduced, the basic error is measured for checked current transformer under the workstation status of light load and full load, and multiplexing output consistency is analyzed for the verification device in this paper. The result data show that multiplexing output consistency has nothing to do with current transformer workstation status, it increases with the secondary load volume increase of checked current transformer and multiplex device has the same influence on amplitude error as phase error. Finally conclusion is drawn that the index of multiplexing output consistency for the device is 30% of maximum permissible error value. It will standardize the manufacture of current transformer verification device and more guarantee measure accuracy and reliability for current transformers. These have certain the value of popularization and application.