This paper primarily introduces a kind of public key algorithm based on the principle of "Trap Knapsack", and gives the construction method of the private key, and analyses cipher length 、 secrecy intensity. 作者主要介绍一种基于“陷门收缩”原理的公钥算法,给出了私有密钥的构造方法,并对密码长度、保密强度进行了分析。