In order to study the effect of irregular seismic loads on soil deformation characteristics, systematic dynamic triaxial tests were carried out on sand samples in this study. In the test, four irregular seismic stress time histories with different peak values and constant amplitude cyclic sinusoidal loads with 20 cycles were applied to three sand samples with different densities for comparative study. The results show that the strain growth curves of sand samples are significantly different under the input of seismic loads and constant amplitude cyclic loads, and the load type and load waveform are the main factors affecting the strain time history development characteristics of soil elements. The correction coefficient obtained by considering the load irregularity is affected by the load type and the relative compactness of sand, and is not affected by the magnitude of the dynamic stress amplitude of the input loads and the type of sand. Finally, for the calculation of soil element deformation under seismic loads, an estimation method based on conventional constant amplitude triaxial deformation test is given.