Abstract: A practical design method of image scaling engine in avionics is presented according to the difference between airborne foreground and background frames.By configuring different algorithms and changing design architecture,the difficulty in unified optimization after image overlay is addressed,which cannot be handled by traditional design.This work begins with the simulation study of the non-edge based and edge based scaling methods.Taking advantage of reconfigurable characteristics of FPGA(field-programmable gate array),two kernel algorithms are implemented in different image processing channels.Finally,a full hardware implementation is realized via FPGA.The experimental results show that the proposed method performs better than the pure bi-cubic algorithm in terms of display effects,and this scheme is of high processing speed and low computational complexity.