A spectrophotometry method for determination of sulfite contents in edible fungus was successfully established and compared with the published National Standard Method(NSM).The method involves nitrogen distillation followed by formaldehyde absorbing and parasosaniline colorimetry.The effects of distillation duration,nitrogen presence and flow rate on testing results were also investigated.The linear range of the calibration curve for sulfite was 0-20 μg.The sulfite detection limit was 0.08 mg/kg with 2.0 g of samples.The relative standard deviation of the proposed method ranged from 1.2 % to 7.8 %.The recovery rate was between 83.1% ～ 99.2%.The most suitable distillation duration was 25 min.Use of nitrogen could improve detection sensitivity by 9-19 %,and the optimal nitrogen flow rate was 0.6-0.6 L/min.This newly established method was validated by 5 licensed laboratories for accuracy.The reported new method has advantages of higher sensitivity,less interference from sample colors and environmental hazards when compared to the NSM.