To develop a damage assessment model applicable to a glued-laminated timber post and beam structural system and gain insights into its behavior under seismic conditions， a series of tests were conducted on four full-scale specimens subjected to horizontal loading. Various aspects， including the presence or absence of braces， different horizontal loading procedures， and two types of K-braces were taken into account. The obtained test results indicate that the failure mode of the pure framework is primarily concentrated at the joints and accompanied by large horizontad deformation. In contrast， specimens equipped with K-braces predominantly experienced failure modes marked by the instability of the brace components. Integrating the K-brace into the glued-laminated timber post and beam structural system effectively enhances the structure’s stiffness and maximum load-carrying capacity while reducing lateral deformations. Additionally， based on the experimental data and the failure characteristics of the specimens， a dual-parameter evaluation model considering deformation and energy dissipation was proposed. This model was capable of reflecting the damage caused by large deformations in the early stages of specimen failure and had the potential to provide a reliable theoretical basis for the reinforcement and design of the glued-laminated timber post and beam structural system and their supported components.