Companies adopted a program called Six Sigma, in order to make fundamental changes in the way the company operated to fulfill customers' expectations. Six Sigma reduces the occurrence of defects. However, in the course of Six Sigma process steps, companies are in the face of problems. This study is to solve the problems using TOC(Theory of Constrains). As a specific case, we review Six sigma's Define phrase. We apply TP(Thinking Process) of Toc for Define Phrase.