The invention relates to a protective agent for a sulfur tolerant shift catalyst. The protective agent comprises a carrier and an active component, and is characterized in that attapulgite clay is used as a main carrier material and added with a powdered solid compound containing magnesium; and the active component is a binary component containing copper and nickel, and added with an active auxiliary agent, which is one or more selected from zinc oxide, iron oxide, chromium oxide, zirconium oxide and corresponding soluble salts thereof. The invention adopts a kneading method to prepare the protective agent, and employs attapulgite clay with wide source and low cost as the raw material. The protective agent not only has the advantages of simple preparation process and low cost, but also has good adsorption detoxification on toxics such as arsenic (As), hydrocyanic acid and carbonyl compounds in the sulfur tolerant shift catalyst. The protective agent can be used in harsh conditions such as high pressure, high space velocity and high water-air ratio, has strong adsorption capacity on ash and toxics in synthetic gas production from heavy raw materials such as residuum, heavy oil, petroleum coke and coal, and can effectively protect the main shift catalyst and prolong the service life of the main shift catalyst.