The goal of Knowledge Management is to maximize profitability and increase organizational effectiveness. Therefore, the purpose of this research is to investigate the effect of knowledge management on competitive advantage with emphasis on the role of intermediary of technology innovation in the beautification organization of Tehran. The method of this research was descriptive and correlation research was a structural equation type. The statistical population of this research includes employees of the beautification organization of Tehran city, which numbered 430 people. 196 of them participated in the study by random sampling method. They responded to knowledge management questionnaires, technology innovation and competitive advantage. Reliability and validity of the tools were examined using Cronbach's alpha coefficient, composite reliability, content validity, and confirmatory factor analysis. The results showed that reliability and validity were acceptable for tools. Data analysis was done at descriptive and inferential levels. In the inferential part, Pearson correlation tests and structural equations are used by least squares (PLS) method. SPSS21 and SMARTPLS software are used to analyze the research data. The results showed that knowledge management has a positive and significant effect on technology innovation. Knowledge management has a positive and significant effect on competitive advantage. Technology innovation has a positive and significant effect on competitive advantage. Knowledge management has a positive indirect and significant indirect effect on competitive advantage.