Abstract: By means of integral equation of vector potential in the time domain and using several simple approximations, the electromagnetic fields on the axis in the far zone are calculated and compared. The attenuation characteristic of electromagnetic energy in the far zone radiated by some electromagnetic pulses are discussed. These pulses include the triangular pulse, the sinusoidal pulse of multiple cycles, the isosceles trapeze pulse, the Gauss pulse and the pulse produced in the experiment of the electromagnetic missile. Some general conclusions and special conclusions are obtained.