The target irradiation uniformity is improved by using two-dimensional smoothing by spectral dispersion and a lens array (LA). A pattern of steep edges and good middle-scale uniformity is obtained with a diffraction-weakened lens array. When two-dimensional spectral dispersion is employed in the laser chain, the beams experience spectral dispersion in two vertical directions, and the fine stripes caused by beamlets interference are smoothed out greatly. If the effect of lateral thermal conduction smoothing is taken into account, the high spatial-frequency intensity fluctuation can be eliminated further. Two-dimensional theoretic results indicate that a flat-topped and steep-edged target pattern can be achieved in this scheme. Because the position of the target does not require adjustment with high precision, the implement of this scheme is comparatively convenient.