The invention discloses a method for analyzing components in an N-Phosphonomethyl aminodiacetic acid (PMIDA) mother solution and relates to a component analysis method for a mother solution generated by producing the PMIDA by using iminodiacetonitrile to serve as a main raw material. The method includes the steps of independently measuring contents of the PMIDA, a nitrilotriacetic acid and an iminodiacetic acid in the mother solution, measuring polybasic acids of the PMIDA, a phosphoric acid and a phosphorous acid and the like in a substep mode, simultaneously strengthening a weak acid by adding calcium chloride, quantificationally releasing inactive hydrogen, then measuring the phosphoric acid, the nitrilotriacetic acid and the PMIDA, and skillfully measuring the contents of the iminodiacetic acid, the PMIDA, the nitrilotriacetic acid, the phosphorous acid, a hydrochloric acid and the phosphoric acid according to reaction laws and interrelations of various substances. By means of verification, the method is accurate, comprehensive, scientific and reasonable, the operation is simple, reliable evidences are provided for recycle and comprehensive usage of the PMIDA mother solution, and the method has a good popularizing value.