The microwave signal was down converted to IF signal by mixing, and was digitalized at IF, then the digitalized signal was delayed by the cyclic access; after that, the digitalized signal was converted back to the analog signal and up converted to the microwave frequency same as the input signal frequency. Based on this process, a 4 300 MHzmicrowave delay line with 70 MHz bandwidth, maximum delay time of 50 μs and delay time hop step of 5ns has been designed at last. The manufactured delay line has the features of good through and triple transmitting suppression.