Removing CO₂, which is the major cause of the global warming, and recycling it to the energy source are very important socially and environmentally. For those, we developed a new process that synthesizes methanol by reacting CO₂ and H₂. First, this process converts CO₂ to CO and H₂O by the water-gas shift reaction. Then, it produces methanol by the methanol-synthesizing reaction. The main purpose of this study is to develop a new process of reducing CO₂ coming from various plants and of producing methanol. This study focuses on designing and cost estimating of the two-step process, using the experimental data of reaction condition and catalyst. The experiments and simulation are done simultaneously to minimize the number of experiments. This study also adopts design hierarchy(Douglas) to find the best flowsheet systematically. By choosing the best one among numerous alternative processes and operating condition, an optimal flowsheet is designed. This new process is also proved to be economically sound compared with conventional methanol systhesis processes.