Abstract: The information of national and provincial highway in Shandong province including pavement structure, traffic load , maintenance history etc, were investigated deeply. The pavement performance model P=P₀1-exp-(α/y)^β was adopted and the parameters of α, β were discussed in detail. Two major factors, ie the thickness of asphalt mixture and large vehicle number per lane in one day, were taken into account, and the parameters α, β in the model P were expressed by the above two factors. The expression of α, β were revised by the bearing capacity of embankment and base type and it could be extended to other provinces after regional environment revision. The α, β could be used conveniently to evaluate the applicability of asphalt thickness in a level of traffic, which could help to make investment decision and maintenance plan for highway department.