Abstract: This paper reviews the application of bounded derivative method in multi-timescale problems Kreiss et al proposed the Bounded Derivative Method and applied it to the initialization of atmosphcric and oceanic motion equations and the derivation of reduced systems,Initialization process can be extended and applied to equatorial and limited,area model,The reduced systems can overcome the severe restrictions on accuracy and stability which are due to the extreme skewness of original system,and will lead to a we...