本文探讨的电子交易规则三级原子数， 是解决电子商务交易规则安全性问题的基本思路。三级原子数从交易规则的安全性角度认为有： 支付、发货与商品送达 （含服务） 三个主要环节， 三级原子数是针对这三个主要环节的安全性提出的要求，安全度逐级提高。认识与理解三级原子数， 可以帮助我们在发展电子商务过程中认识与解决安全性引起的各种问题 This article explores the electronic trading rules three atomic number, is to solve the basic idea of ​​the security of e-commerce transaction rules. Three atomic number from the perspective of trading rules of security that there are: payment, delivery and delivery of goods (including service) three main links, three atomic number is the security requirements for the three main links, security Degree by level increase. Understanding and understanding of the three atomic number, can help us understand and solve the problems caused by security in the process of developing e-commerce