From the perspective of communication countermeasure，the performance and application characteristic of distributed jamming are analyzed，as well as the relation between the distributed density and jamming probability. The Joint Tactical Information Distribution System(JTIDS) is carried out by using Simulink，and the effect of distributed jamming on JTIDS system is simulated. The methods of effective jamming of distributed jammer on JTIDS system are discussed. Some beneficial conclusions are given，which will be useful in the war.