With a total 761 contact binary systems in Svechnikov & Kuznetsova(1990)'s cat- alogue, their physical properties by the mass ratio are inverstigated - for the early CE type with a common radiative envelope and the late CW type with a common convective envelope. It is found that the early CE type shows a higher temperature difference( £ü¡âT£ü) between the primary and secondary components, and also long period, than the late CW type. The mass ratio of the CW type are distributed in smaller ranges, from 0.3 to 0.7, than the CE type. Further, the relation between mass ratio and luminosity for the CW type shows a well-defined linear relation, such as L2/ L1 = 0.01 +0.89q. In the mass ratio-radii relation, it is con rmed that the physical difference of the CE and CW types is a result of the secondary radius. A new mass ratio-radii relation for the CW type is suggested for both the total radius(r1 + r2) and the radius ratio(r2£¯r1 ), respectively.