The invention discloses a design for a low-oscillation dispersion mirror structure. The structure comprises a substrate, a chirped film system structure and an ultralow-refractive-index layer. The structure is characterized in that the ultralow-refractive-index layer is additionally arranged on the top part of the chirped film system structure and is realized by an inclined deposition technology, the refractive index and thickness of the ultralow-refractive-index layer can be controlled by adjusting the rate and angle of inclined deposition, and the refractive index of the chirped film system structure can be well matched with an air layer, so that the dispersion oscillation can be greatly reduced. Due to the designed structure, the dispersion oscillations of dispersion mirrors with different bandwidths and dispersion amounts can be greatly reduced, and the dispersion mirror design needs for low loss, low oscillation and large dispersion compensation amount for pulse compression in an ultrafast laser system are well met. The low-oscillation dispersion mirror structure can be applied in the ultrafast laser system (such as a chirped pulse amplification technology and an optical-fiber laser), and is an essential dispersion compensation element in the ultrafast laser system.