Abstract: Elastic adjustment-QR method for system reliability analysis of tall building structures is presented. First of all, the QR method for the analysis of tall building structures is introduced. Next, elastic adjustment-QR method for plastic limit analysis of tall building structures is presented. This method is based on the theorem of lower limit, elastic compensation and QR method, and it is a new method for plastic limit analysis of structures, overcoming the defects of analyzing tall building structures by plastic hinge-finite element method. At last, a new method for system reliability analysis of tall building structures is presented. The principle is as follows: Find the plastic limit load by the elastic adjustment-QR method; Establish limit state expression in terms of plastic limit load; Find reliability index of structures; Find system reliability by reliability index. This method avoids the difficulties and defects of finding collapse mechanism for tall building structures, and simplifies the computation of failure probability.