Target tracing in real time has a grea t significance on the field of auto-control and on-line detection.A novel meth od is presented in this paper for moving target detecting and tracing with XOR o perating of two images.Also,the design on hardware of interface with the compute r system for calculation above is given in this paper.The speed of circuit calcu lation is nearly two times of pure program instructions by experiment,and this m ethod will be the first choice for target tracing in real time. -