To solve the problems of difficult treatment of desulfurized gypsum and overmining of limestone, a kind of lime/gypsum flue gas desulfurization (FGD) collaborative desulfurized gypsum resource utilization process (LCS) was proposed. The system mainly includes the LCS-LFGD (lime/gypsum flue gas desulfurization system), LCS-C (desulfurized gypsum reduction calcining process), and carbon monoxide-coupled activated carbon reduction of SO₂ to sulfur process (LCS-S). Taking a typical wet FGD unit of 300 MW power plant in China as an example, the limestone/gypsum flue gas desulfurization system (L-FGD) process was compared with the LCS by using the method of life cycle assessment and life cycle cost (LCC). The result shows that the overall environmental impact of the LCS is 0.2913. The environmental impacts of LCS-LFGD, LCS-C, and LCS-S were 0.1322, 0.1543, and 0.0048, respectively. Both LCS-LFGD and LCS-C are the key processes in this case study, and electricity consumption and coal gas consumption are the key substances in each key process. LCC analysis showed that although the initial investment of LCS was 4.32 × 10⁶ USD ∼5.76 × 10⁶ USD more compared with L-FGD, the running cost of LCS was 1.41 × 10⁶ USD per year lower compared with L-FGD. Besides, the cost of ore mining, the quality of calcined products, and environmental protection policy will affect the financial cost of the process.