Abstract: Time history analyzing method is one of accurate methods of assessing structures� behavior against earthquake. In spite of this, this method requires spending plenty of time and volume of calculations especially in structures with high freedom degrees number. One method is proposed in this article to simplify used accelerograms in time history analysis using the concept of hit loading. In this proposed method, accelerogram is equalized to a limit number of pulse sequence which is entered to structure in various times. The number of these pulses can be more or less depending on the required accuracy and length of earthquake record and main structure period. The severity of each one of hits is equivalent to the rate of energy of earthquake is a part of record that mentioned pulse is equalized instead of that as an initially recommendation in this study, the distance of two sequenced points with zero velocity in earthquake record is considered as the limitation of each pulse in a way that the area under the curve of accelerogram be equal with the rate of equivalent strike. The time of applying this hit is also considered in center of mentioned area under accelerogram. Through adding structure responds against each one of hits , structure respond will be calculated in different moments, using a number of various samples with periodic times and different rates, the efficiency of proposed method has been shown. Numerical results show that maximum displacement spectrum resulted from this method has an approximate error of 5% while the volume of done calculations has been reduced more than 15 times toward time history with main record.