The invention provides a method for desulfurating and denitrating and recovering sulfur resource in a closed cycle way, comprising the following steps: 1, dedusting; 2, desulfurating and denitrating; and 3, recovering sulfur resource. The method can effectively solves the problems of the prior art such as difficult treatment of secondary products, secondary pollution, high working cost, single product and the like. According to market requirement, analysis reduction regeneration of desulfurated secondary products is fully utilized, aiming at treating waste with waste to serve multiple purposes, recovering the wasted sulfur resource in flue gas of fire coal with the lowest cost, improving the comprehensive added value of desulfurated secondary products and reducing working cost thereof, dedusting, desulfurating and denitrating, and recovering sulfur resource to realize long-term efficient working, self-sufficient closed cycle, resources and energy conservation, low energy consumption, and no waste water discharge and secondary pollution, thereby meeting the requirements of resource recovery and environmental management, and improving economic benefit and social benefit for enterprises.