Abstract:In this paper, the determination of phosphorus in leaching solution of rare earth phosphate rock by ammonium molybdate spectrophotometry was studied.The effects of the amount of developer and the acidity of nitric acid on the determination of phosphorus were investigated by experiments. the accuracy and precision of the method were also investigated.The experimental results show that the precision of the method is good, the relative standard deviation is less than 3%. Compared with the gravimetric method for determination of phosphorus, the results of the two methods are consistent. The method can accurately detect the phosphorus in the leaching solution of the associated rare earth phosphate rock.It was a simple, rapid and accurate analytical method for investigating the leaching rate of phosphorus in the hydrometallurgical process of rare earth phosphate rock.