Abstract: Current architecture specifications for structural design is based on reliability calculation of structural members, which considers little systematic characters of structure and cannot reflect integrated structural reliability. Therefore, a method of resistance adjustment for structural system was put forward in this article, which consisted of two steps, i.e. reliability analysis of structural system and reliability adjustment to structural system. The main reference for resistance adjustment to structural system is that according to ratio of reliability index for every failure mode to responding target reliability index, we can distribute and adjust reliabilities for every failure mode. So that reliability index of structural system could be used as parameters in architecture structural design, which is a simple and practical way of structural reliability design. It is concluded through the reliability analysis of structural system of a double layer and twin spans frame that it needs a few major failure modes to work out the failure probability of frame structure system with limited calculation error, which can meet the requirement for engineering design.