In order to improve the security of public traffic, In the road engineering, traffic engineering facilities for basic theory,analyze the factors that affect public transport safety,and then conduct extensive questionnaire,analyze the degree that the major transport facilities affect the safety of traffic,determine the evaluation index and use the analytic hierarchy construct public transport safety evaluation system.Finally,applicate evaluation system to determine the best time for preventive maintenance of road markings,and also provide a new way of thinking for the study of traffic safety.