Abstract: The asbestos-free calcium silicate heat-resistant material composition, comprises:(A) 100 parts by weight of a mixture of lime and siliceous material having a CaO/SiO.sub.2 mole ratio of 0.6-1.2;(B) 20-170 parts by weight of xonotlite obtained by hydrothermal synthesis;(C) 15-150 parts by weight of fibrous wollastonite; and(D) water in an amount of 2-8 times as much as that of the total solid contents and is produced by a method which comprises the steps of:(i) molding a slurry of a uniform mixture of that recited above in (A) to (D).(ii) steam curing said molded body in an atmosphere of steam under a pressure of not less than 6 kg/cm.sup.2 to react the siliceous material with the lime; and(iii) heat treating said steam cured product to remove water therefrom at a temperature of not lower then 100.degree. C. under atmospheric pressure.