Since 1960s the United States and the former Soviet Union have been carrymg out plas'ma research because plasma can absorb or reflect radar electromagnetlc waves. Up to now they have applied plasma stealth technology to some weapons. This has attracted much attentlon of domestlc experts. This paper explains why and how plasma can mterfere with raclar waves. By analyzing the advantages and disadvantages of the technology , It conc1udes that plasma stealth technology can be applied to military aeroplanes after three mam problems are solved.