Abstract: The model of efficiency-cost ratio for after-shock masonry strengthening is established, considering the number of stories, material strength, seismic damage, the promotion of seismic capacity, and the engineering cost. Based on the model, the optimal selection method for masonry strengthening is proposed, combining the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), including the construction time, technology, durability, and the impact on architectural function. Comparative cases are performed to study the influence on the optimal selection results by the number of stories, by the material strength, and by the seismic damage level. It is concluded that: the proposed method can reflect the influence on the strengthening decision making by the basic structural conditions, and effectively provide a scientific and reliable scheme for masonry buildings, combing the subjective and objective factors during the preliminary design stage.