In order to establish a rapid and accurate hydride generation-atomic fluorescence spectrometry method for the determination of selenium content in water samples, the influence factors on Se nitrolysis in the water such as nitrolysis temperature and the amount of hydrochloric acid were studied. The authors determined a simple and practical test method that is to add 3 mL hydrochloric acid at 3 ℃. We measured the precision and accuracy of the method by the standard liquid of 3, 6 and 10 μg·L-1, and the test results were 2.96, 5.43 and 9.66 mg·L-1.The recovery varied from 90.50% to 98.67%. Meanwhile we tested 29 water samples by different methods. The error of standard sample was 8.95％～25.46％by hydride generation-atomic fluoresence spectrometry in the GB/T 5750.6—2006, and the error of standard sample was 1.33％～3.40％ by new method. Compared with the national standards of GB/T 5750.6—2006, the method has the advantages of operating simplicity and and easy control, and it is also reliable and economical.