The invention provides an earthquake stacked section determining method and an earthquake stacked section determining device. The earthquake stacked section determining method comprises steps that prestack earthquake data is acquired; the normal moveout correction processing of the prestack earthquake data is carried out twice to acquire first processing data; the first processing data is separated by horizontal filtering, and a first interference signal and a valid signal are acquired; the reaction correction processing of the valid signal is carried out by using the first interference signal, and the prestack earthquake data after interference elimination is acquired; the normal moveout correction processing of the prestack earthquake data after the interference elimination is carried out to acquire second processing data; the horizontal stacking of the second processing data is carried out to acquire the earth quake stacked section. By using the horizontal filtering, the separation of the valid signal and the interference signal of the prestack earthquake data after the two times of normal moveout correction processing is carried out, and the prestack earthquake data after the interference elimination is acquired, and therefore the technical problem of the prior art of inability of acquiring the earthquake stacked sections having high signal-to-noise ratio and high resolution at the same time is solved.