The problem concerning information asymmetry and quality uncertainty in the used automobile market of China has not been settled in a better way for years. Therefore, how to convey the signal of quality to the customers is of great value for used automobile dealers. On the basis of defining the probability of quality evaluation and for the purpose of achieving per expected revenue maximization, this paper builds a model of quality - contingent pricing and thus makes the optimal pricing and discount policy. In addition, this paper displays directly, through data analysis, the impact of the used automobiles pricing policy on the enterprise profits under the context of information asymmetry.