Due to the similarity of passengers source in long distance transportation, competitions among passenger dedicated line(PDL), existing railway lines and air transportation are severely. First of all, analyzing the element which influence travelers choice, then a competition model for these three modes of transportation are gotten, which mainly take ticket price, comfort and travel time into account. In the process of competition, the ticket price adjustment can affect the service quality. Therefore, in this paper using the average crowding degree to measure service quality, under the promise the guarantee of the service quality of transportation modes, a PDL ticket price model based on the service quality is formulated, and the LINGO software be used to solve this model. At last the PDL of Jing-guang is chosen as an example to calculate the ticket price of PDL. The result shows that in order to meet the required of service quality of each transportation mode, the ticket price of PDL should no less than RMB 700.