A series of complex was synthesized using phenyl hydroxamic acid and metallic chloride, and used for catalytic aquathermolysis of heavy oil at low temperatures for the first time. The effects of water content and catalyst concentration on aquathermolysis were investigated. And then a tri-component coupling aquathermolysis of water-heavy oil-methanol was designed and the reaction conditions were investigated. With the catalyst and methanol, the reaction occurred at temperatures as low as 180A degrees C. The viscosity of the product was also substantially reduced by the decomposition of the large hydrocarbon molecules.