Aiming at the problem that the image dehazing algorithm has halo phenomenon in depth discontinuity and legacy residual fog in the distant area, this paper proposes a single image dehazing algorithm based on fusion and Gaussian weighted dark channel. Firstly, using the characteristics of image morphology gradient, the morphological gradient image and the dark channel image are linearly fused to obtain the fusion dark channel. Secondly, the adaptive Gaussian weight parameter is constructed to pixel-by-pixel process the fused dark channel image to obtain the coarse transmission, and the L1 regularization is used to optimize the transmission. Finally, the haze-free image is restored by the atmospheric scattering model and the restored atmospheric light value. Experimental results show that the proposed algorithm can recover the details of the image and suppress the halo phenomenon. The objective comparison with several typical algorithms proves the feasibility of the proposed algorithm.