Abstract: Coking test and hot tube test were used to study the high temperature detergency and additives action rules of solvent-refining base oil from the conventional process and hydrogenation-isomerization dewaxed base oil from the most advanced process by means of contrast research. Anti-oxidation properties, the changes of total base number and carbonaceous deposit structure during the coking test were (also) studied. The results indicate that the high temperature detergency and additive sensitivity of two base oils are obviously different, which are caused by their different structures; the two base oils show their own antioxidation properties and additive consumption rules respectively in the course of coking test; test results and analysis by FT-IR indicate that metallic salts including carbonate, sulfate and carboxylate (deposited) on metal surface under the simulation test conditions.