Abstract: The sample of human red blood cell was treated to haemolyze with hypisotonic cold Triton X-100 solution by ultrasonic vibration.The the sample solution was diluted one hundred times,and the contents of Zn,Fe and Mg were directly determined by FAAS.The values of detection limit (3S/N) and RSD′s (n=7) for Zn,Fe and Mg were 2.44×10-3,2.85×10-2,1.56×10-3mg·L-1 and in the ranges of 0.69%-1.03%,2.85%-3.84%,0.92%-1.22%,respectively;The method was applied to the analysis of a same sample of mixed human red blood cell,and the results obtained were in consistency with those obtained by the acid digestion method.Values of recovery of the 3 elements were in the range of 95.0%-110.0%.