The invention provides a continuous casting crystallizer copper plate detection device and belongs to the technical field of metallurgy. The continuous casting crystallizer copper plate detection device solves a technical problem that the thermocouple of a conventional detection device is inconvenient to disassemble and assemble and is poor in detection accuracy, and comprises a box body with an opening on the top; a vapor output unit communicating with an external vapor generating unit and capable of evenly discharge the vapor into the box body; a crystallizer copper plate disposed in the boxbody and fixed to the top of the box body; a cover plate covering the top of the box body and having the crystallizer copper plate located under the cover plate; multiple thermocouples evenly distributed on the cover plate, penetrating through the cover plate, detachably connected with the cover plate, and each having one end in contact with the crystallizer copper plate. The crystallizer copperplate is heated by the vapor inside the box body and the thermocouples can detect the crystallizer copper plate. The vapor heating method solves a defect that a carbon rod can only integrally heat thecrystallizer copper plate, and guarantees that the copper plate is evenly increased in temperature.