In this talk, we first give a briefy summary of the main topics in Kaehler geometry related to the existence and uniqueness of the extremal Kaehler metrics(KE metric is a special case of the ex. Ka. metric). Then we discuss the recent joint work with Tian on Kaehler Ricci flow on KE manifolds with positive bisectional curvature. We prove that the flow always converge in such settings.