Abstract: To solve the problem of the narrow band gap of seismic metamaterials based on surface wave theory, a low-frequency and wide-bandgap seismic metamaterial based on cross fractal columns was designed in this paper, and the dispersion curve of the designed structure was calculated by numerical simulation. It is found that the relative band gap width of the third-order cross-fractal seismic metamaterial is as high as 60%. The dispersion curve of cross-fractal metamaterials of different orders was comparatively studied to clarify the mechanism of the band gap expansion of fractal seismic metamaterials. Through material parameter analysis, the influence of different material parameters on the width and position of the band gap was studied. To verify the shielding effect of the designed seismic metamaterial against actual seismic waves, time-domain and frequency-domain analyses were carried out. Through the transient dynamic analysis of El Centro seismic wave and Taft seismic wave, it is found that the third-order cross-fractal seismic metamaterial can reduce the acceleration amplitude of the two seismic surface waves in the band gap frequency range by more than 50%, which indicates that it has good isolation seismic performance.