The magnetic lens(Zumbro lens) is a critical part in proton radiography. Traditionally the matched beam for Zumbro lens in proton radiography is a virtual point source beam, which is not suitable for some cases, such as cylindrical samples. In these cases, a parallel beam is more appropriate. In this paper, a method, which uses quadrupole beamline, is proposed for designing a magnetic lens with parallel beam matched. Theoretical analysis is given. The results show that the matched beam for this lens is indeed parallel beam, while the major merits of Zumbro lens are inherited. Following this method, a theoretical design based on the 11-Me V cyclotron is presented. The magnetic lens (Zumbro lens) is a critical part in proton radiography. Traditionally the matched beam for Zumbro lens in proton radiography is a virtual point source beam, which is not suitable for some cases, such as cylindrical samples. parallel beam is more suitable. In this paper, a method, which uses quadrupole beamline, is proposed for designing a magnetic lens with parallel beam matched. Theoretical results are given. The results show that the matched beam for this lens is indeed parallel beam, While the major merits of Zumbro lenses are inherited. Following this method, a theoretical design based on the 11-Me V cyclotron is presented.