The invention discloses a method for solidifying carbon dioxide by utilizing water produced from a high-salinity coal-bed gas field, and belongs to the field of environmental engineering. The method comprises the following steps: CO2, fly ash, desulfurized gypsum and water produced from the high-salinity coal-bed gas field are injected into a first stage reactor; a mixture obtained after the firststage reaction enters a second stage reactor, CO2 is injected into the second stage reactor at the same time, and the CO2 escaping from the first stage reactor is also injected into the second stagereactor; the mixture obtained after the second stage reaction enters a third stage reactor, and the CO2 escaping from the second stage reaction is injected into the third stage reactor; the mixture obtained after the third stage reaction enters a fourth stage reactor, and the escaped CO2 is injected back into the first stage reactor; the mixture precipitated in the fourth stage reactor is transported to an abandoned pit for seal and storage, and supernatant partially flows back to the first stage reactor. The method is simple in operation; by utilizing cheap materials such as the fly ash, thedesulfurized gypsum and the like, and water produced from high-salinity coal-bed gas fields, CO2 can be effectively sealed and stored, and at the same time, the problem of the treatment of water produced from the high-salinity coal-bed gas fields is solved.