In communication system, for the different application, it's need antenna provide different pattern, such as cosecant squared pattern, The antenna with cosecant square pattern can rapidly find object, and cover the larger effective region, so the antenna which have cosecant squared pattern is widely used in the radar system. This article will analyze how to use E-plane metal lens to realize beam forming, and designed a kind of E-plane metal lens which can realized cosecant squared beam forming in 9.5GHz.