Contextual mobile advertising, which has the advantages of strong interactivity and immersive experience, will be the development direction of Internet advertising in the future. Although past research has explored the effects of contextual mobile advertising, little research has studied the effect on consumers’ behavior from the perspective of contextual advertising traits. Thus, this study combined the Scene Theory and the Theory of Planned Behavior to construct the model of advertising effectiveness mechanism. By analyzing survey data from a representative sample of 340 mobile consumers, the validity of the model was proved. The results showed that contextual stimulation, contextual interaction, and content accuracy, as contextual factors in mobile advertising, can positively influence consumers’ attitudes toward mobile advertising, which in turn stimulate purchasing intention. The theoretical and practical implications of these findings were also discussed.