A composite optical isolator of one-dimensional magneto-photonic crystals was presented. The 4×4 transfer matrix method used to investigate the optical isolation property of this isolator. When the angel between applied magnetic field and optical axis of optical path is 19.95°,with the total thickness of 20.16 μm,it can realize the optical isolation around 3.1 nm. When the incident angle is 3.9°,it can also realize the optical isolation around 1.06 nm with flat-top responses. The structure can realized broadband isolation,flat-top responses and has great tolerance of incident angle at the same time. It has a high valuation in practical application.