Under the influence of such factors as plasma density, exciting power, air pressure, it is difficult to solve plasma antenna parameters, for example, gain, radiation pattern. This paper uses time domain difference method to build a model of plasma antenna excitation and radiation driven by electromagnetic wave, and shows the influence of different parameters on plasma axis density distribution, for instance, exciting power, collision frequency, plasma delay time, ionization energy. In addition, it explains the linear and non-linear distribution of plasma density on different exciting occasions. Furthermore, it solves the wave vector distribution and radiationpattern of signal transmit by plasma antenna.