In many practical applications, it is required that the spot is ring distributed. Therefore, it is important to do the experimental research of converting the terahertz Gaussian beam to a ring beam. In the paper, a phase plate was designed using GS algorithm, converting the Gaussian beam with frequency of terahertz band to a ring beam. The shaping effect of multi-order encoding phase plates was discussed. According to different transmission distances, different simulations were done. Using the PyrocamⅢ as the recording device, beam shaping experiments were carried out on different distance. The experimental results show that the experimental results are close to the simulation results.