Based on the calculation of labyrinth seal leakage rate, the factors influencing the leakage rate are described. Three characteristics such as seal profile, throttling gap and number are analyzed respectively. The results show that round profile is avoided for higher leakage rate. Better seal effect is got to choose a smaller seal value for throttling gap changing linearly with leakage rate. The more is throttling number, the fewer is leakage rate. But with the increasing of throttling number, throttling effect is not better and the economic cost is higher. So the appropriate throttling number is needed to be chosen in the design. Experimental results show that engineering application demands are met by electro-optical turret labyrinth seal design.