Abstract: The resilience of subgrade soil is an important mechanical parameter in pavement design. The design value of subgrade soil intensity often adopts the modulus of resilience testing under the most disadvantageous season. The influence of the changes of water contents to subgrade soil intensity are not taken into account. This paper analyzes the law governing the variation of the subgrade soil resilient modulus with the season water contents. Lessons were drawn from pavement relative damage thought that different season create in design method of AASHTO. An equivalent subgrade soil resilient modulus formula is deduced. It is proposed that the design value of subgrade soil intensity replaces the most disadvantage season module with the equivalent subgrade soil modulus of resilience. The proposed method can advance non-deformability of soil base and integer design strength of asphalt pavement.