Abstract: Loss is a comprehensive index of structural seismic performance. In order to evaluate the rationality of moment magnifying coefficients of concrete frame structures in the current national seismic code, a method of seismic loss calculation was proposed. The method was based on structural fragility analysis and the loss calculation frame FEMA P-58, and was from the viewpoint of seismic loss risk. Four reinforced concrete frame structures with moment magnifying coefficients of 1.1, 1.3, 1.5, 1.7 were designed. The fragility curves and fragility matrixes were obtained by using the incremental dynamic analysis. According to the seismic intensity probability model, the probability distribution of various seismic intensity of the site was given. The 50-year and annual monetary and human losses of every structure were calculated. The results indicate that the seismic loss risk will decrease with the increase in moment magnifying coefficient. The 50-year total monetary loss ratio ranges between 0.08 and 0.12. The human loss ratio ranges between 4.85×10^-4 and 1.12×10^-3. The seismic loss risk is acceptable if the structure is designed to the current national design code.