There is a problem that structure design and materials design are disjointed about the asphalt pavement with semi-rigid base in our country. In order to solve the problem and prevent pavement from damaging early due to the promblem, the paper studied structure characteristics and function characteristics and reasonable thickness of every asphalt layer in the asphalt pavement with semi-rigid base, and reseached into the asphalt mixture design method based on the layer contribution theory systemically.Firstly, the paper analysed the formation mechanism of the fatigue crack in asphalt pavement with semi-rigid base. Having carried out the mechanics research with the viscoelastic layers system theory and the computer program, the paper finds that the stretching stress due to the load accords with a certain law along vertical in the asphalt coat at usual temperature. While the contact conditions of all layers in pavement are continuous completely, there is no stretching stress due to the load in the asphalt coat at usual temperature. While the contact condition of the asphalt coat with the base is continuous partially or slippery completely (the other contact conditions of the layers in pavement are continuous completely), the stretching stress due to the load increases gradually from the top position to the bottom position in the asphalt coat at usual temperature, and the value of the stretching stress at the bottom position is the maximum value in the asphalt coat. So the paper reaches the conclusion that the leading area to resist fatigue lies at the asphalt lower coatSecondly, the paper analysed the formation mechanism of the temperature contraction crack in asphalt pavement with semi-rigid base. Having carried out the mechanics research with the temperature contraction stress calculation formula educed by Hills and Brien, the paper finds that the temperature contraction stress increases gradually from the bottom position to the top position in the asphalt coat at low temperature, and the value of the temperature contraction stress at the top position is the maximum value in the asphalt coat. So the paper reaches the conclusion that the leading area to resist the temperature contraction crack lies at the asphalt top coatThirdly, the paper analysed the formation mechanism of the rut on asphalt pavement with semi-rigid base. Having carried out the mechanics research with the viscoelastic layers system theory and the computer program, the paper finds that the shear stress τ_(max) due to the load increases gradually from the top position and the bottom position simultaneously to the middle position whose depth is 7 centimeter in the asphalt coat at high temperature, and the value of the shear stress τ_(max) at the middle position whose depth is 7 centimeter is the maximum value in the asphalt coat. So the paper reaches the conclusion that the leading area to resist rut lies at the asphalt middle coat, and that the asphalt upper coat and the asphalt