High molecular weight poly(methylsilylene) is obtained in a good yield through dehydrogenative condensation of methylsilane catalyzed by (C5Me5)2NdCH(SiMe3)2. At a high temperature, polymerization process involves cross-linking via the loss of methane. Pyrolysis of the resulting polymer gives beta-SiC in a high yield. Blend with a carbon-rich polymer like poly(phenylsilylene) is effective to prevent the formation of contaminative metallic silicon during ceramization.