The unsteady flow behaviors in devices like gas wave machines, wave rotor refrigerators and so on are complex due to real gas effect at high operational pressure and low temperature. In this work, a detail computational model for unsteady flow analysis of real natural gases is established. The real effect on unsteady behaviors of natural gases in shock tubes have been studied extensively. Results show that the non-classical flow of the gases will not exist. The discipline of reflection and refraction of various gas waves or discontinuities remain unchanged for natural gases. Attention should be paid only to the deviations between perfect gas model and real gas model for gasdynamic waves.