In recent years, many buildings went up in flames one after another. It is thought-provoking. So the fire-proof property should be considered into one of the most important performance of the building thermal insulation materials. As a result, the study on the expanded perlite lightweight porous inorganic material heated up fast although its application still has some problems to be solved. In this paper, we take the expanded perlite as raw material to make thermal insulation board, and then study on the effect of volume weight on the coefficient of thermal conductivity and tensile strength. What is more important, we find that a new binding agent of Na2O-B2O3-SiO2 syetem sol contributes to improving its water resistance.