Abstract: The content of organic matter in slaughterhouse wastewater is relatively high and its color is deep. The tranditional analytical method for the determination of total phosphorus by ammonium molybdate spectrophotometry is very complicate. In this paper, the samples were evaporated to dryness and calcinated, and then the content of total phosphorus in slaughterhouse wastewater was conveniently and quickly determined by inductively coupled plasma mass spectrometry(ICP-MS). The proposed method was validated by the analysis of real samples. The recovery was 95.2%~102.0%. The method is accurate and reliable, with a wide measurement range and high efficiency, and it can provide certain reference to analysts.