In this paper, plasma main characteristics such as electron mean temperature, electron number density, and oscillation frequency have been measured experimentally using the double Langmuir probe diagnostic system. In our experiment, the plasma was generated by applying the low pressure dc glow discharge in several common gases. The experimental results indicated the highest plasma density and oscillation frequency for the plasma originating from Argon and the highest mean value of temperature for Hydrogen plasma. The experimental results were then confirmed by COMSOL simulator, showing reasonable consistency with the simulations. The data were then used to compare the degree of ionization with the measured plasma parameters.