Abstract: This paper presents a novel test device for evaluating the integral scattering characteristics of the extinction material in spaceborne telescopes. By employing the scattering theory, the device enables a more comprehensive measurement of the scattering characteristics, facilitating a better understanding of the material’s behavior. The paper discusses in detail the integral scattering theory, system construction, and system performance. The system is further modeled and simulated, leading to the conclusion that the scattering characteristics of the extinction material exhibit significant variations at different points and incident angles. Notably, the system is capable of measuring the scattering characteristics under various conditions, thereby providing a comprehensive distribution of the material's scattering behavior. This comprehensive and accurate scattering characteristic distribution serves as a valuable reference for targeted design, stray light measurement and suppression, development of high-performance optical instruments, and research in computational optics. Moreover, it establishes a solid foundation for material selection, characteristic investigation, stray light analysis, and suppression in spaceborne telescopes employed for the detection of gravitational waves.