Abstract: To make full use of solid waste resources and explore the potential value of steel slag used in the field of inorganic insulation building materials, steel slag foamed concrete was prepared by using equal amount of steel slag instead of cement, then the effect of water content on its thermal conductivity was investigated by the method of heavy humidity; and the relationship between the temperature and its thermal conductivity was studied by changing the temperature of the hot plate of the thermal conductivity tester; finally the change rule of thermal conductivity of steel slag foamed concrete in natural environment was also studied by applying periodic temperature and humidity to simulate the actual environment. The results show that the thermal conductivity of steel slag foamed concrete increases with the increase of water content, but the increasing tended to be lower and lower; The thermal conductivity of steel slag foamed concrete increases with the increase of temperature, and there is a good linear-relationship between them; The thermal conductivity of steel slag foamed concrete is increasing with the cycle of periodic temperature and humidity, and the increasing tends to be lower and lower too.