Abstract: A random number generator which generates a variable assuming any given probability distribution is designed based on prefix code and programed.The probability space is firstly expanded by decomposing each value to several temporary symbols.Each symbol is allotted a probability of power of a given integer，and the summation of these powers approximate the probability of corresponding value in original space repectively.Then a prefix code is constructed in the new space and used to code a uniform sequence.The effect of the generator is validated by experimental result.

Key words: random number generator, prefix code, probability distribution expand, series of power

摘要： 设计并实现了生成任意给定分布随机变量的随机数发生器。根据指定精度将随机变量的概率分布用幂级数扩展，构造前缀码，利用前缀码对均匀分布的随机序列编码得到结果。数值实验证实了该算法的有效性。

关键词: 随机数发生器, 前缀码, 概率分布扩展, 幂级数