The illegal parking problem of motorcycles and bikes is always regarded as a typical social dilemma. The individual behavior is the result generated from the entanglement of maximizing personal interests and personal moral consciousness in the context of social dilemma. The previous studies indicated that the structural strategy, i.e. punishment and reward, is a good way to force people to cooperate under social dilemma. However, the cost of structural strategy to some extent is high and becomes a burden of local government. The previous studies also pointed that moral consciousness existing in the mind also has significant effect on changing human behavior. Therefore, the psychological strategy is regarded as an assistant role of structural strategy to solve the social dilemma problem like illegal parking problem in the city centre. The purpose of this study is to investigate the effect of the application of psychological strategy on solving illegal parking problem of motorcycles and bikes in the city centre. The follow-up method is adopted in this study to collect panel data. The undergraduate students are treated as the subjects (sample size = 178). The subjects are assigned into 4 groups in this study. Each group receives a corresponding type of information (persuasive communication). The information lets them figure out the present state of illegal parking problem of motorcycles and bikes in the city centre and show the ways of solving those problems. Then, this study investigates whether the provision of different information causes the subjects behavioral change by second questionnaire survey. Consequently, the effectiveness of persuasive communication upon decreasing illegal motorcycle and bike parking is confirmed. This result supports that in order to resolve social dilemma, the psychological strategy which may make up the structural strategy to a certain extent should be incorporated in urban transportation plan, urban facility management plan and urban plan.