To asphalt pavement, because asphalt is polymer materials, the aging of asphalt cannot be ignored; bituminous mixture is made up of asphalt and aggregate, meanwhile it contains interior pore space. Because of the rheology behaviour of bituminous, bituminous mixture will emerge viscous-plastic deformation under traffic load, and because of the porous in it, the water which enters the pore will make the bituminous peeling off from aggregates. It is just the environmental influence that leads early damage of asphalt pavements. Analysis on the design of asphalt pavement shows that long-term environmental influence is not directly consideed. To be more accurate to consider the influence of environment on the asphalt pavement, based on structural reliability theory gradation and porosity of asphalt mixture are proposed to be added into design indexes, on the same time it is proposed that detection should depend on the core samples drilled on the spot and the bond status of interlayer should be included in the acceptance indicators.