This standard specifies the determination method of phosphorus content in niobium and its compounds, which is applicable to the analysis of phosphorus content in niobium, niobium hydroxide and niobium carbonation. The 4-methyl-pentanone-[ 2] extraction separation of phosphorus-molybdenum blue Spectrophotometric method, spectrophotometry and Inductance coupled plasma atomic emission spectroscopy (AES) method (ICP-OES) are used, and the determination range is 0.0010% to 0.080%. Spectrophotometric method, spectrophotometry is the arbitration method when the ranges overlap. This standard provides a reliable analytical tool for the mass detection of niobium materials.