Abstract: The hydride generation-atomic fluorescence spectrometrc determination of trace arsenic in chromium ore smelting slag is preseuted. The prefreatment of the sample is the use of the wet decomposition by nitric and perchloric acid with the addition of thiourea and ascorbic acid to reduce arsenic. The recovery of the method was 96.2%~102.0%, and the relative standard deviation:IF=5034.6c+7.8, correlation coefficient: 0.9994. The test verified that the method is simple, rapid, accurate and reliable with a wide moasurement range and is an effective detection method, which also provides a scieatific basis for the impact of ore smelting waste on the environmental protection.