Pyrolysis polycondensation of polysilane has been executed at different temperatures, pressures under catalyst/ no catalyst conditions in an autoclave reactor. Progress of polymerization was followed as a function of several process parameters such as temperature, pressure, intrinsic viscosity, average molecular weight and catalyst. Process analysis revealed that temperature and pressure had significant influence on the structure and properties of polycarbosilane. Gel permeation chromatographic data and intrinsic viscosity measurements confirmed the formation of polycarbosilane with average molecular weight up to 6300 Da. Average molecular weight, conversion and yield increased with use of catalyst. FT-IR and 29Si NMR established that structural formation and bonding network during the silane to carbosilane transformation as a function of process conditions.