We have calculated the Hugoniot properties of shocked nitromethane based on the improved Tsien's equa- tion of state (EOS) that optimized by "exact" numerical molecular dynamic data at high temperatures and pressures. Comparison of the calculated results of the improved Tsien's EOS with the existed experimental data and the direct simu- lations show that the behavior of the improved Tsien's EOS is very good in many aspects. Because of its simple analytical form, the improved Tsien's EOS can be prospectively used to study the condensed explosive detonation coupling with chemical reaction.