Plasma has excellent electric conductivity. Compared to ordinary metal antenna, plasma antenna which uses Plasma as an electromagneticenergy conductive medium, has greater stealth, smaller volume, lighter weight, and dynamically refactoring features.Therefore, study of plasma antenna is of great significance. This paper uses the numerical simulation based on MATLAB to study the antenna radiation field problem. As is shownin the results: thecurrent distribution map and radiationpattern will changeaccordingly with the changes of antenna length, density and other parameters. That is to say, the radiation direction is controllable.