Before the large capacity and engineering image is analyzed carefully, which need to be effective scaled. The subsequent analysis and calculation to engineering image is subjected by image quality and scaling time. According to scaling research of large capacity engineering image, the effect for image scaling by various interpolation algorithm is individual analyzed, and more appropriate algorithm is selected. The experimental results show that the engineering image of best effect is got, when it is high-expansion scaled by double cubic interpolation, and the bilinear interpolation is more suitable for low multiple scaling image.