Abstract: Light forsterite thermal insulation materials were synthesized by molten salt method using forsterite powders with particle sizes of 44 ,74 ,250 μm,respectively,and NaCO3 as raw materials,at sintering temperatures of 900,1 000,1 050 ℃ and 1 100 ℃.The effects of forsterite powder particle size and sintering temperature on the phase composition,density and compressive properties of sintered samples were studied.The results show all sintered samples were composed of Mg2SiO4,Na2MgSiO4 and MgO,but were different in phase content.The higher the temperature and the smaller the particle size,the lower the apparent porosity,the higher the bulk density and compressive strength of the sintered samples.The sintered sample with forsterite powder particle size of 74 μm sintered at 1 000 ℃ had better pore distribution and high strength,whose bulk density and compressive strength were 1.76 g·cm-3 and 12.31 MPa.