NOVELTY - A method for utilizing molybdenum in waste cobalt-molybdenum-based catalyst system involves leaching molybdenum from the system using aqueous potassium salt solution to convert it into a water soluble powder material, which is further reacted with cobalt salt and ammonia water to form a complex into which a carrier is dipped to form cobalt-molybdenum-system sulfur-tolerant shift catalyst product.    USE - For utilizing molybdenum in waste cobalt-molybdenum-catalyst system to form cobalt-molybdenum-system sulfur-tolerant shift catalyst (claimed) useful in a sulfur tolerant shift process for converting coal or residual oil based raw materials into e.g. ammonia, hydrogen, synthesis gas.    ADVANTAGE - The method provides simple processing; has low cost; does not cause the environmental pollution; and provides improved molybdenum recovery rate i.e. at least 90%. The prepared sulfur tolerant shift catalyst has low cost with same performance as that of the same kind of industrial catalyst.    DETAILED DESCRIPTION - A method for utilizing molybdenum in waste cobalt-molybdenum-based catalyst system involves:    (1) crushing the waste catalyst into a powder, passing through 200 mesh sieve, and detecting MoO3 content of resulting powder (C1);    (2) in an autoclave, adding deionized water; powder (C1) and an alkaline aqueous solution of potassium salt, under basic conditions to obtain a slurry A; adjusting pH, filtering to obtain a filtrate, adding an acid to the filtrate to adjust pH to 6-7, and then filtering and removing the precipitate of aluminum hydroxide impurity to obtain a filtrate B; evaporating filtrate B to obtain a water-soluble powder material C, detection potassium content of the resulting powder;    (3) preparing sulfur resisting change catalyst according to a state of art dipping method, where to the water soluble powder (C), is added water-soluble cobalt salt, followed by adding ammonia water to form complex solution; setting a carrier in the complex solution by dipping and drying after roasting at 400-650 degrees C to obtain the finished product i.e. sulfur-tolerant shift catalyst having potassium (K2O) content of 2 to 10 wt.%; MoO3 content of 2-12 wt.% and CoO content of 0.5 to 5 wt.%.