Abstract: Ammonium sulfate products have a sustainedly growing consumption space in China′s fertilizer，industry，and export application fields.The ammonium sulfate′s capacity growth of traditional industry and of by-product of flue gas desulfurization is difficult to meet the requirement of consumption growth.Preparation of ammonium sulfate from phosphogypsum has the advantage of wider capacity increasing space.The domestic industrial preparation technology of ammonium sulfate from phosphogypsum is mature，and the better use of its by-product calcium carbonate slag is to be the acidic soil improver.The influence of product sales price on the project acceptable ammonia price and on required capital subsidy is quantitatively analyzed，and the project economically viable sales prices with and without capital subsidy are given.It is also pointed out that the preparation of ammonium sulfate from phosphogypsum will have a good development prospect in some conditional enter prises of high-concentration phosphoric compound fertilizer.

Key words:  , phosphogypsum；ammonium sulfate；calcium carbonate；profitability