A method for estimating setting of seismic risk for performance-based seismic design. The estimating method considers the exceedance probability of a performance level, determines a structural performance level by setting an exceedance probability, determines a seismic demand when the performance level is constant, sets an exceedance probability of the seismic demand, and combines same with the setting of seismic risk of a seism, so as to finally determine a seismic motion input, thereby establishing a probabilistic seismic risk estimating method reaching a certain performance level. The present method enhances design control and objectives.