It analyzes in deep the whole course of rules and methods of the same name variable quoting separately from four aspects that is parameter in shape and parameter in fact,memory space assign,compound statements,external variable and inside variable.

There is hypothesis in traditional strategic academic theory that customer is enterprise exterior variable, so every theory scholar attempts to cultivate core competence from the bottom of enterprise.

by restricting and managing the test cases based on the given quality model, then proposed an evaluation method of software external quality referring to the test case results, and gave an example.