本文证明了短期个别风险模型当理赔次数随机变量为0-1分布时,可以寻求一个短期聚合风险模型与之等价;更为重要的,当个别风险模型的索赔次数随机变量服从较小参数的Poisson分布时,也可以寻求到一个复合Poisson分布与之近似。为此,本文解决了一些特定风险损失随机变量和的分布计算问题,Panjer迭代是其计算基础。 This paper proves that short-term individual risk model can seek a short-term aggregate risk model when the number of claims is 0-1, and more importantly, when the number of claims of individual risk model follows a smaller parameter Poisson distribution, but also to find a complex Poisson distribution and its approximation. For this reason, this paper solves the problem of distributional computation of some random variables sums of risks and losses, Panjer iteration is the basis of calculation.