Aiming at solving the problems of remote sensing images with poor clarity, contrast and color fidelity in foggy weathers, a rapid defogging method using dark channel prior is proposed based on the characteristics of large amount of data, small changes in depth and almost no area of the sky. To ensure the performance of defogging, the dark channel image is obtained by calculating the minimum value of r, g, b channels. It significantly reduces the complexity and avoids heavy computation. Experimental results demonstrate that the improved algorithm can remove the haze effectively. It can enhance the definition and color of hazy degraded image, and the processing time is 2% of the original method. The proposed algorithm can satisfy the requirement of real-time remote sensing image processing.