The invention provides a device and method for quickly testing a metallurgy slag high-temperature heat-conducting coefficient. The problem of generally and quickly testing the influence on a heat-conducting coefficient measurement by the radiation heat transfer of a transparent/semi-transparent medium under the high-temperature condition is solved, the rapid testing on the heat-conducting coefficient of the metallurgy slag at different temperatures is realized, and heat-conducting coefficient condition of the material under different temperature conditions in the 55-1300 DEG C temperature range can be measured at once within short time, thereby obtaining a temperature-heat-conducting coefficient curve; the vacuum degree can be controlled in the testing process, and the in-situ record and storage are performed on the temperature condition in the experimental process by using a high-resolution infrared temperature measurement system and a built-in thermocouple; the method has the features of being wide in testing range, fast in testing speed, and convenient for preparing a to-be-tested sample; and a faster and more practical method is provided for testing and researching the physicalperformances of the material.