The effective elastic thickness (Te) is a useful measure of the integrated strength of the lithosphere to resist the flexural deformation. The Te values of various regions and tectonic provinces can be obtained, and a comparison from region to region can also be made. The methods , models and controlling factors of T, are introduced in this paper. Since it is closely related to the thermal, mechanical and rheological structures of the continental lithosphere, the study of Te is very useful to put constraints on them.