Scanning probe microscopy (SPM) has great potential to understand site specific surface processes while preparation of catalysts and the role of surface defects in chemical reactions, which are key issues for developing metal oxide catalyses. In this talk, I will review our SPM studies on CeO@sub 2@(111) and Al@sub 2@O@sub 3@/NiAl(110) surfaces. CeO@sub 2@ is used for catalysts, fuel cells, etc., and their high oxygen transport and storage capacities are important for the applications. By using noncontact atomic force microscopy (NC-AFM), we have succeeded in visualizing various kinds of surface oxygen defects and highly mobile oxygen atoms around metastable multiple defects that are not reconstructed for stabilization.@footnote 1@ Activation energy for hopping of the mobile surface oxygen was estimated to be about 30 kJ mol@super -1@ from the consecutive SPM imaging of a slightly reduced CeO@sub 2@(111) at 300-400 K. We have also observed high reactivity of oxygen atom facing to the oxygen defect for extraction of hydrogen atom from the methoxy intermediate. We have been applying nonvolatile precursors for preparation of catalyst model surfaces. Water solution of [Rh(OAc)@sub 2@]@sub 2@ is ejected through a pulse-valve to a well ordered Al@sub 2@O@sub 3@/NiAl(110) under ultrahigh vacuum. By slowly annealing the precursor- adsorbed surface to 493 K, the Rh precursor decomposed and homogeneous metal clusters that contain 2-4 Rh atoms were observed by STM. It can be explained by decomposition kinetics of the precursor molecules. Finally, I will briefly introduce chemical identification of surface intermediates by using a single 'molecular tip' that can be switched by external light irradiation.@footnote 2@ @FootnoteText@ @footnote 1@ K. Fukui, S. Takakusagi, R. Tero, M. Aizawa, Y. Namai, and Y. Iwasawa, Phys. Chem. Chem. Phys. 5, 5349-5359 (2003).@footnote 2@ D. Takamatsu, Y. Yamakoshi, and K. Fukui, J. Phys. Chem. B 110, 1968-1970 (2006).