Abstract:  Ionospheric delay is one of the most important resources in satellite navigation systems, and TEC map reconstruction is the major way to eliminate the delay effect of the satellite navigation systems. Basing on the ionospheric delay effect, there is a way to improve the quality of SAR imaging by using the TEC of the propagation grid. The simulation of the low frequency SAR imaging shows an intense effect of the ionospheric delay. The SAR imaging gets an improvement correcting by the TEC of the propagation area.