This study proposed a design method for a double spherical reflection compensation detection system to detect the surface accuracy of a large aperture high-order aspheric surface. A spherical surface tangent to the edge as the best-compared sphere was selected. The aspheric gradient and normal aberration of the high-order aspherical mirror was also fitted with an outer diameter of about 860 mm and a middle hole of about 200 mm. The formula of the compensation detection system was derived using the three-stage aberration theory, and was utilized to calculate the initial parameters, analyze the compensation effect, and improve and optimize the final structure. The wavefront root mean square of the system was less than 1/90λ by optical software simulation, and 98% tolerance analysis results revealed that the wavefront is less than 1/40λ, which meets the actual detection requirements. This method can solve the problem of inability to detect high-order aspherical mirrors to be inspected.