From simply offering airline services to providing elaborative and various commercial services, the transportation of airports implies the importance of stimulating purchasing power of travelers to enhance airport revenues. Although the importance of airport retailng has been widely recognized, relevant research has been relatively scarce. This study aims to establish a conceptual model of passenger shopping behavior at airports based on the Theory of Planned Behavior. A two-stage survey was conducted in Taiwan Taoyuan International Airport; 301 and 105 valid questionnaires were collected in the first and second stages, respectively. The reliability and validity of constructs were examined with Confirmatory Factor Analysis while the direct effects of attitude, subjective norm, anticipated affective reaction and perceived behavioral control on purchase intention of passengers and the mediating effect of attitude between subjective norm and purchase intention were examined through Structural Equation Modeling and regression models. The analysis results showed that: (1) Attitude, positive anticipated affected reaction and perceived capacity were significantly and positively related to purchase intention. (2) Hedonic shopping value and injunctive norm exerted a significantly positive influence on purchase intention, which was further mediated by attitude. (3) Environmental atmosphere demonstrated a positive significant effect on after-purchase attitude, which together with atmosphere and decision convenience showed a positive effect on customer loyalty; among which, environmental atmosphere had the greatest effect among them. Finally, the conclusions and suggestions were proposed based on the results.