Abstract: The glint error is one of the important error sources in radar tracking on extended target. In practise, the lose-possibility has been risen greatly in teams of the glint error of the scattering wave in radar tracing and guiding system. So the research of glint error can improve the accuracy of tracing target. The visual method was developed to compute the glint error of complex targets by the phase gradient method in GRECO(graphical electromagnetic computing) system in high frequency region. This method made each pixel of screen as one scatter center of target and the number of scatter centers was greatly increased to the pixel level, then the result accuracy was improved and the visual computation course was implemented. The glint result of the two-ball target model wascompared with the measured result and proved its validity. Meanwhile, the complex target glint was also proposed in this visual platform. And, the lose-possibility of an traced missile was also given.