Abstract: Some criteria analyses were made to investigate the effect of rotating,etc. On leakage flow and heat transfer in labyrinth seals.A series of analogous criteria for experimental simulation were driven from the method of directional unit system.The principle of directional unit system is suggested that the choice and treatment of the unite system in the similarity theory is quite different from those of public unit systems such as SI system or engineering unit system,even though all they must conform to the Gauss's rule of unit system.For the former,the flexibility and the particularity is necessary,because in the similarity theory the particular and actually phenomenon is investigated,and for the directional unit system, the invariance and the universality is necessary,as it is based on possibility of occurrence of all phenomena.Those analogous criteria are proved to be reasonable and practicable by discussion.