The invention relates to a tool for optimizing a power-off routine electrical test procedure of a transformer and particularly relates to a portable transformer high-voltage test universal transfer box. A transformer to be tested and a test instrument are connected through the transfer box, when the connection relationship between the test instrument and the transformer needs to change, the switching of a connection mode can be completed through directly rotating a transfer switch, which is convenient and quick, many shortcomings of a traditional test mode are made up, thereby the whole test process is optimized, the work efficiency is improved, and a power-off time is saved.