The asphalt pavements which are designed for 15-years usage are often highly damaged in the early period. In order to eliminate this phenomenon, researches have been carried out in many aspects, but the situation of asphalt pavement damage cannot be essentially changed. In the view of reliability, the frequent early stage damage phenomenon of asphalt pavements means that nowadays process of asphalt pavements must have not sufficient reliability, and just it leads the asphalt pavements can not reach the design purpose. Based on the basic engineering reliability theory, the reliability of the asphalt pavement design, from the determination of effect actions to selection of material parameters and the calculative model about pavement, has been analyzed; meanwhile the reliability of construction process has been analyzed too. The analysis on the reliability of asphalt pavement shows that the determination of design parameters makes the actual material is weaker than design; the construction process of the asphalt pavement makes the asphalt mixture greatly different anticipations and makes the layer condition deviated the ideal bonding condition. It is just these various uncertainties in design and construction that causes the asphalt pavement damage in early stage. So in order to change the situation of early damage in asphalt pavement, the effective measures are to focus on the reliability of design and constructions.