A vast number of ancient masonry buildings exist in China, many of which have become representatives of Chinese culture and civilization. Masonry structures are continually exposed to natural environments like temperature changes, rainfall, and monsoons, leading to deterioration such as cracking, loosening, powdering, and spalling, primarily caused by freeze-thaw cycles. To evaluate the current condition and remaining service life of existing masonry structures, an evaluation method based on symptom reliability was employed. The symptom hazard function and logical vectors characterizing different structures were introduced, the relationship between symptom-based reliability and cumulative symptom hazard function was established. Meanwhile, the relationship of the symptom hazard function and symptom values measured under single symptom was also established. Based on the commonly used Weibull model for structural symptom-damage curves, the variation of structural reliability with symptoms and the evolution of remaining life with symptom-based reliability were obtained. Furthermore, a three-story masonry building was employed as a case study, a FEM model was developed to analyze the performance degradation under freeze-thaw effect. The maximums of both Von Mises stress values and nodal vertical displacement values were treated as symptoms of building’s reactions, the curves that illustrate the variation of structural reliability with different symptoms were obtained. In practical engineering applications, maintenance strategy can be determined according to the reduction of symptom-based reliability.