Abstract: The sensitivity of the time-history reliabilities of the anti-lateral displacement capacity of a reinforced concrete (RC) frame and the load-bearing capacity of its elements to its structure parameters under frequent earthquakes is analyzed using the time-history reliability algorithm. In addition, the effect of the correlation coefficient of seismic acceleration, as a random variable, on the time-history reliability is discussed. The result shows that changes in the section size of beams and columns, the mass of a storey, the ratio of reinforcement and the strength of steel bars have a great effect on the time-history reliabilities of the load-bearing capacityof beams and columns of aRCfarme, while the variations ofthe elastic modulus of RC, the section size of beams and columns and the ratio of damping will influence the time-history reliabilities of the anti-lateral displacement capacity of RC frames.