The mother liquor wastewater generated during the production of iron phosphate had high sulfate ions，total phosphorus（TP），ammonium ions，and total hardness.To prevent scaling of wastewater during reuse treatment，effective pre⁃treatment was necessary.The removal effect of different agents on the easily scaling anions and cations in wastewater was studied by chemical precipitation method.The results showed that when 22.5 g/L（pH=9.0） calcium hydroxide was added to the wastewater，TP was 0.14 mg/L，and the removal rate reached 99.97%.The sulfate ion concentration dropped to 1 525 mg/L，with a removal rate of 97.07%.Phosphate ions were added to the wastewater and pH was adjusted with ammonia water.When the amount of phosphate ions added was 2 500 mg/L（pH=8.5），the total hardness was 110 mg/L，the total hardness removal rate reached 97.82%，TP was about 20 mg/L，and the absolute dry sludge amount was 7.32 g/L.The addition of calcium hydroxide could reduce the amount of scale anions and TDS such as phosphate and sulfate ions，while the addition of phosphate and ammonia could reduce the total hardness of wastewater，which was the amount of cations.The above two dosing methods achieved effective pretreatment of iron phosphate wastewater，avoiding scaling during membrane concentration and zero discharge processes，and were feasible methods for pretreatment of iron phosphate wastewater.And ASPEN PLUS software was used to simulate the process of adding calcium hydroxide to wastewater to generate calcium sulfate and analyze the specific heat capacity of calcium sulfate.