The design method of a Newton optical system with a zero-power corrector,where the stop is before the primary mirror,is discussed in detail. By moving the stop,changing the eccentricity of primary mirror,selecting the power of the corrector,and calculating the rays of the system concerned,the optimized optical system solution is obtained,various design curves and results are given,and the optical system is evaluated. Take Newton optical system for an example,where the clear aperture Φ is 300,relative aperture A is 1/2,field of view θ is ±5°,the corrector's power ■₁₁ is 5,its aberration coefficients S₁ can achieve 0.000002λ,S₂ is 0.000025λ after optimization,the wavefront aberration is 0.3174λ at 0° field of view,and 90.9861λ at ±5° field of view.