In order to investigate the adaptability between traffic & transportation and social-economy development and to provide decision-making basis for decision-makers to optimize the traffic & transportation structure and improve the supply-demand adaptability, the information entropy theory was applied with the adaptability between the supply structure and demand structure of passenger transportation as the object of study, the insufficiency of the present theoretical research and its inadaptability with practice were pointed out, the factors influencing the supply structure and demand structure of passenger transportation were analyzed, and the entropy models of the supply structure and the demand structure of passenger transportation were set up respectively. The entropy model for evaluation of the adaptability between the supply structure and demand structure was constructed to provide the evaluation criterions and method. The results show as follows: The supply of the gross passenger traffic volume is needed to meet the demand of the gross passenger traffic volume, and the supply structure is also required to suit the demand structure; the entropy values of the supply and demand structures need to be consistent, the entropy functions should share the same changing trend and velocity; the relative deviation coefficient of the entropy functions tends to reach 0, the adaptability degree tends to reach 1.
