Multi-beam antenna technology can be used to improve the utilization of spectrum resources and channel capacity, which has attracted much attentions. Transformation optics has been widely used to design various kinds of antennas and has become a research hotspot in recent years. In this paper, an area mapping method was initiatively proposed to design a multi-beam lens antenna. The implementation method was discussed. The performance of the antenna was verified by simulation. Research results show that the designed multi-beam lens antenna based on the area mapping method can exhibit a nonmagnetic and piecewise homogeneity material parameter distributions, and can be synthesized by drilling hole in the dielectric substrate or using equivalent medium. The proposed multi-beam lens antenna can be used to reshape the radiation direction of the dipole antenna, improve the radiation gain, and achieve multi-directional radiation.