An atmoic Fluorescence spectrometry for the determination of micro arsenic in animal liver was developed with high sensitivity and fine accuracy. Under the selected experimental conditions, there was a linear relationship,,hip between the fluorescence intensity and arsenic concentration in the range of 0-160ng (.) mL(-1) with correlation coefficient of 0.9966. The limit of detection was 0.4ng (.) mL(-1), and the recovery was 94.2%-98.5%.