Abstract: Several high power microwave (HPM) technologies have matured to point where they are ready for the transition from engineering and manufacturing development to deployment as operational weapons. Now, an attack on Iraq is expected to see the first use of microwave weapons. This paper briefly presents HPM weapon technology development programs of U.S, U.K and Russia. The significant research progress of some typical HPM weapons are reviewed, and finally the technical challenges and developing prospect of HPM weapon systems are discussed.