Abstract: The process of using phosphogypsum and ammonium carbonate to prepare ammonium sulfate is an effective way of comprehensive utilization of phosphogypsum.Some methods and conclusions about the byproduct calcium carbonate residue made by previous researchers were introduced.However，high impurity content influenced products′ quality when it was used to produce light calcium carbonate and being as the raw material of cement.It also pointed out that the decomposition of calcium carbonate residue by the suspension preheating-decomposition-cooling process to produce lime was a suitable treatment method，and the research conclusion was introduced.At last，it was proposed that the application of as-prepared active lime in sewage treatment will be the next step in the research.

Key words: phosphogypsum, calcium carbonate residue, comprehensive utilization