In order to solve the problem that the traditional defogging method based on the dark channel priori is easy to cause artifact and color distortion in the edge region and the sky region, a dark channel image defogging method based on regional transmittance fusion is proposed. First, the fog image is divided into three regions: non sky, sky, and transition edge. Then, the non-sky region and transition-edge region are fused in the dark channel combined with block transmittance estimation and point transmittance estimation, and the fused dark channel transmittance is obtained using gradient domain guided filtering. Next, the luminance transmittance of the sky region and the dark channel fusion transmittance are synthesized to obtain the final transmittance. Finally, the image is restored using the obtained transmittance and the improved atmospheric light value to obtain the defogging result image. Experimental results show that the proposed method is significantly better than the traditional dark channel method. It can effectively suppress edge artifacts and preserve the color features of foggy images. Compared with the traditional methods, the defogged images obtained by the proposed method can achieve better results in both subjective and objective evaluation.