Copper slag based ferrous oxalate cement (CS-FOC) has great potential application prospects in the fields of repairment of highStemperature kilns and stabilization/solidification of nuclear wastes due to its properties such as fast-setting and high early age strength. In this study, the evolution of properties, phase compositions and structure of CS-FOC after exposure to elevated temperatures was comprehensively researched on the basis of our preliminary studies. The results showed that the compressive strength can reach 55.1 MPa when naturally cured for 28 days, and it was mainly composed of new-formed ferrous oxalate dihydrate (FeC2O4.2H2O) and unreacted fayalite (Fe2SiO4). The compressive strength and structure of CS-FOC changed regularly after exposure to elevated temperatures. When treated at higher than 250 ℃, the formed FeC2O4.2H2O started to decompose into iron oxide, and the strength decreased because of the destroyed structure. The strength can stably keep at about 15 MPa after exposure to the temperature of 1000 ℃. Thus, CS-FOC has better thermal stability than ordinary Portland cement and remains at higher level compressive strength.