According to the characteristics of the structure performance degradation, after analyzing such factors as the structural durability failure state, reliability level, environmental load and resistance, the durability limit state equation considering steel corrosion initiation, concrete cover cracking and maximum corrosion induced damage value is established for the durability design under chloride environment. Based on the design theory of reliability, the partial coefficients of load and resistance are introduced to reflect the target reliability requirements of structural durability, and subsequently the partial coefficient expression form of structural durability design is established. According to the principle of the same reliability level for probability design and partial coefficient design, the determination method of partial coefficient for resistance and their values under different durability limit states are presented.