Abstract: Weibel instability is studied by three dimensional particle in cell simulation code LARED-P. The generated magnetic field and currents by Weibel instability present filamentary structure. When the Weibel instability reaches the saturation stage, the current filaments begin to interact with each other. The relativistic electron beam deposits part of its energy into the plasmas through instabilities. For 10 MeV electrons, when the beam electron density concentrates 5% of the total electron density, 14% energy of beam can be deposited at last. The dispersion relation in this case also deduced, the growth rate is obtained in some simple cases.