Based on customer loyalty, this study explores the relationship among service quality, customer satisfaction, and customer loyalty in a telecommunications industry. It uses telecommunication company's mobile phone users as the main research object and adopts a convenient sample questionnaire. Collect data and effectively recover 300 questionnaires. The statistical analysis of the data was conducted by factor analysis, correlation analysis and regression analysis. The research results show: (1) The service quality has a significant positive effect on customer satisfaction. (2) Customer satisfaction has a significant positive effect on customer loyalty. (3) Customer satisfaction has a significant positive effect on customer loyalty.