In the research on laser driven inertial confinement fusion, laser-plasma interaction (LPI) is a key issue of affecting ignition. Many beam smoothing technologies are proposed and adopted to suppress the instability of laser-plasma. To obtain a smoother focal spot, the smoothing by spectral dispersion (SSD) technology based on bundle multiple-frequency modulation is proposed and studied theoretically. The technology adopts one modulation frequency in one single beam, and then a bundle of multiple beams with different modulation frequencies focuses on one point. The results indicate that intensity modulation caused by interference of multiple beams can be suppressed and the uniformity of far field intensity distribution can be improved by the proposed technology. Compared with the traditional multiple-frequency modulation SSD technology, the proposed technology has a better smoothing performance when the color cycle number is closer to practical situation.