Abstract: A theoretical analysis was conducted on the formula to calculate the leakage rate of labyrinth seals considering actual gas parameters and on the equation for the flow control. Based on the rotor multi-frequency elliptic vortex method, the effects of medium category and real gas parameters on the static and dynamic characteristics of labyrinth seals were studied. Results show that the molar mass of gas is positively correlated with the leakage rate of labyrinth seals. At the same frequency of rotor vortex oscillation, the absolute values of direct stiffness coefficient and of main and cross damping coefficient increase with the rise of the molar mass of gas. The flow force increases as the molar mass of gas rises, and the flow force of medium CO₂ is 1.63 times as much as CH₄. As the frequency of vortex oscillation increases, the influence of molar mass on the damping coefficient gradually transfers from the inertial effect to the frictional effect, therefore, as the molar mass of gas increases, the effective damping coefficient increases at low frequency and decreases at high frequency.