Most studies about customer satisfaction and word-of-mouth communication were discussed how customer satisfaction brought word-of-mouth communication. And to word-of-mouth communication, researches were referring to the motive of word-of-mouth communication, how word-of-mouth communication been measured, or the impact to the customer decision behavior. However, we missed a critical factor that might change the whole story - word-of-mouth cognitive difference. For it is possible that the factor switch a casual loop from a negative loop to a positive one. This study using System Dynamics is adept in dealing with issues like dynamics complexities, casual feedback, time delay, taking the word-of-mouth cognitive difference as a factor in the case model. Moreover, simulate the variety of word-of-mouth cognitive difference in different scenario. The result indicates under the structure of this case, high expected word-of-mouth cognitive makes positive word-of-mouth into negative. That means while a person has higher expected to a word-of-mouth, it might leads him expect higher service satisfaction. Once it failed, the situation turnover. Nevertheless, it should be over concerned the actual simulations are not so conspicuous. The appropriate speaking is under the influence of word-of-mouth cognitive difference, shows the pattern of word-of-mouth cognitive acts on customer satisfaction.