Abstract: This paper introduces the real-time imaging process of an airborne SAR radar, and gives a method to modify the initial coordinates of the interpolation function of thechirp rate for the problem of resolution in the acture imaging processing.The phenomenon of real-time imaging processing and matlab processing error is analyzed, and the problem is solved by double precision floating point operation in real-time processing.The final imaging results show that the real-time imaging process can work reliably and obtain the ideal image.