Objective:To establish a method for the determination of trace mercury in spirulina powder by microwave digestion and cold atomic-absorption spectroscopy. Methods:After microwave digestion, mercury in Spirulina Powder was oxidated to the state of the ion of mercury, then the sample was detected by mercury analyzer. Results:A good linear relationship was obtained from the concentration of mercury range 0-5.00 -滋g/L,r = 0.9999,the detection limit was found to be 0.013 -滋g/L,and the experimentally determined average value for mercury in China standard reference material of Mussels(GBW08571) was found to be in good agreement with the certified value,recovery of methazolamide was between 90%-108% with the relative standard deviation(RSD) of 4.7%-Conclusion:The method of microwave digestion and cold atomic-absorption spectroscopyc was simple,sensitive, and suitable for determination of trace mercury in spirulina powder.