In order to improve the water damage resistance and durability of asphalt pavement in South China, the improved skeleton dense asphalt concrete is used to design the undersurface structure. According to the selection of raw materials, the design of target mix proportion and the design and verification of production mix proportion, the mixture proportion parameters of excellent rutting resistance, water damage resistance and fatigue resistance are determined. The construction technology and key points of the lower sealing layer and ancillary engineering before construction are introduced. The mixing production parameters of asphalt mixture, the setting of transportation vehicle, the setting of mechanical parameters of mixture paving operation, the scheme comparison of mixture rolling process and the dynamic monitoring of construction temperature are determined. The construction segregation and thickness uniformity of asphalt pavement are evaluated by non-destructive techniques such as nuclear-free densitometer and three-dimensional ground penetrating radar. Through the refined management of raw material control, mix proportion design, functional layer and mixture construction of the undersurface layer, the smoothness, compactness, thickness and other pavement performance of asphalt pavement can be significantly improved, which is an economic and effective way.