Aiming at the obvious block effect,color distortion and low brightness of the traditional dark channel prior algorithm in processing foggy images with large areas of sky,a dehazing algorithm combining regional growth and tolerance mechanism is proposed.Firstly,the dark channel is obtained by gray scale image etching;Secondly,the sky region is segmented by the seed region growth method,and the average gray value of the sky region is estimated as the atmospheric light value;Then,combined with the atmospheric scattering model,the rough transmittance is obtained,and the improved tolerance mechanism and guided filtering are used to modify and refine the transmittance;Finally,Retinex method is introduced to post-process the image to further adjust the color and brightness.The experimental results show that the dehazing algorithm proposed in this paper has obvious dehazing effect when processing the image with sky region,the color of the sky region has been significantly improved,and the image is clear and bright as a whole.