采用曲线分段拟合方法，把我国立筒库磷化氢环流熏蒸过程中释放与降解的变化规律进行数学建模，并在IBM—PC486电子计算机上利用Mathematica2.0版本建模、求解、绘图、修匀，然后对求得的模型进行分析和检验。结果表明：函数模型（Ⅰ、Ⅱ、Ⅲ）具有良好的预测功能，能分别预测磷化氢环流熏蒸中的浓度峰值，磷化氢降解到无效低浓度熏蒸需要的时间和害虫的磷化氢熏蒸临界浓度。 Curve fitting method was used to simulate the law of release and degradation of phospholipid circulation fumigation in China. The model was solved by Mathematica2.0 on IBM-PC486 computer , Smooth, and then analyze the model and test. The results show that the function model (Ⅰ, Ⅱ, Ⅲ) has a good predictive function, which can respectively predict the peak concentration of phosphine in circulating fumigation, the time required for phosphine degradation to ineffective low concentration fumigation and the phosphine fumigation of pests Critical concentration.