This paper discusses the relationships between Critical Success Factors (CSF) of knowledge Management (KM) with Competitive Advantage (CA) in automotive industry (Saipa corporate in IRAN). In this research, four categories were used including Human-Oriented factors, Organization, Technology and Management process and their relevant component as independent variables. The research method is based on a descriptive-survey research. The questionnaire includes all CEO and board of director of all firms who worked for Saipa Co, covering 88 companies with 160 managers. To test the hypotheses, SPSS and LISREL software packages were used. For data analysis, descriptive statistics and inferential statistical tests (structural equation modeling, Pearson correlation coefficient) were used. Results taken from structural equation modeling (SEM) proposed measurement model fit and construct validity. Pearson correlation shows there was meaningful relationship between four categories of CSF of KM and CA when the level of significance was 0.001.