The propagation model for the laser quads in the hohlraum based on broadband laser beam smoothed using ISI and de-DLA has been built in this study, aiming at the optical path arrangement scheme and cylindrical target hohlraum structure of the NIF, and then the irradiation characteristics of the laser quads on the hohlraum wall have been analyzed and optimized. The results show that the mismatch between the focal length of the primary lens and parameters of the cylindrical target hohlraum will cause varying degrees of damage to the envelope of the laser spots on the hohlraum wall for beams with different incident angles, as a result of the laser spots overlapping on the hohlraum wall, the irradiation uniformity on the hohlraum wall greatly diminishes. The effect of the principal lens focal length, the number of DLA sub-lens, and the long and short axes ratio of the sub-lens on the intensity distribution of the laser quads on the hohlraum wall are discussed on this basis. The optimization of these parameters, such as the principal lens focal length, number of DLA sub-lens, the long and short axes ratio of the sub-lens, and incident angle of the laser quads, achieves the improvement of the irradiation uniformity on the hohlraum wall. The results show that increasing the focal length of the primary lens appropriately can effectively retain the envelope of the laser spots on the hohlraum wall for beams with different incident angles, minimizing the overlap of the laser spots on the hohlraum wall. Besides, the duty ratio of laser spots on the hohlraum wall increases, and the time required for beam smoothing reduces when the number of DLA sub-lens and the long and short axes ratio of the sub-lens are optimized. Furthermore, after optimizing the incident angle of the inner cone laser quads, the overlap of the inner and outer cones laser quads on the hohlraum wall is eliminated.