The invention discloses a phosphogypsum soil conditioner capable of stabilizing a soil structure. The soil conditioner is prepared from the following raw materials by weight: 33 to 35 parts of chicken manures, 8 to 10 parts of potassium monohydrogen phosphate, 16 to 18 parts of red mud, 3 to 4 parts of EM microbial inoculum, 4 to 6 parts of abandoned lime peels, 2 to 3 parts of cobalt sulfate, 4 to 5 parts of calcium hydrogen phosphate, 130 to 140 parts of phosphogypsum, 12 to 16 parts of oil sediments, 7 to 9 parts of soda residues and a proper amount of water. The phosphogypsum soil conditioner provided by the invention is added with a variety of biological bacteria of ecological environment of the soil and is enriched in the content of organic matters of the soil; thus, when in use, the soil conditioner can reduce soil bulk density, increases the content of aggregates with a size of 0.25 to 0.50 mm, improve buffer capacity of the soil and reduce breakage rate of the aggregates at the same time, and has good effects on increasing stability of soil aggregates and improving the soil structure.