A MoM-PO hybrid method is proposed to solve some unusual electromagnetic (EM) radiation problems those cannot be solved by the traditional EM computation methods. By using this method, the antennas are divided into two regions, which are meshed by trigonal patches, and then RWG basis functions are defined in two regions. The methods of moment (MoM) and Physical Optics (PO) are used respectively in two regions, and the matrix equations are obtained. By solving equations, current distributing can be obtained. The numeration results show that MoM-PO hybrid method is more accurate than the traditional methods. The computation work done by using MoM-PO is greatly decreased compared with that done by using MoM. Simultaneously the computational efficiency is increased without losing validity. It is an effective EM numerical method.