Along with the continuous development of aerospace technology, human exploration of outer space has made great progress. During this period, a large number of vehicles have been launched into orbit around the Earth by various countries, led by the United States, but due to a lack of awareness and technology to recover them, they have resulted in space garbage and debris remaining in outer space. According to incomplete statistics, there are thousands of pieces of space debris with a diameter of 10 cm around the Earth, which pose potential hazards for future space exploration and research. Early detection and identification of space debris and timely avoidance are the primary means to ensure the safe operation of satellites and spacecraft. Long-range detection and imaging technology is key to obtaining the relative position information of space debris.For space-based detection and imaging tasks, a reflection system without chromatic aberration is generally used due to the strict requirements on aberration. Among these systems, the three-mirror anastigmat system (Three-Mirror Anastigmat, TMA) is a reflective optical system that can meet the requirements of anastigmatism and a flat image field. Generally, it can be divided into a coaxial three-reflection optical system and an off-axis three-reflection optical system. The coaxial tri-reflective system has the advantages of small size, light weight, good thermal stability, and mature technology, but the disadvantage of reduced system resolution due to central blocking; while the off-axis tri-reflective optical system has a large field of view, no central blocking, and a simple structure, but is difficult to process and adjust and is also susceptible to the influence of external environmental factors, which limits its use under certain conditions. In this paper, by designing the co-axial eccentric-pupil, the center blocking is avoided. The structure is simpler than the traditional coaxial system, while retaining the advantages of the coaxial system in processing and assembly. To further improve space utilization and achieve lightweight and miniaturization, a common aperture spectroscopic structure is adopted. This allows for both high-resolution passive visible light imaging and three-dimensional imaging capabilities using active short-wave infrared imaging. The working principles of the two detection methods differ, as do their applicable occasions, thus eliminating the limitations of a single detection mode and greatly extending the application scope of the entire system.In the front-end optical system design, through the optimization of the initial off-axis structure, we complete the design of the co-axial eccentric-pupil afocal system, with an entrance pupil aperture of 300 mm, an F-number of 8.33, and a full field of view of 0.12°×0.12°. The reflected light from the beam splitter enters the passive imaging system in the back-end optical system. The passive imaging system operates in the 450~850 nm spectral range; the energy distribution within the circular area surrounding the image element is greater than 80%, and the dispersion spots for each field of view are within the Airy disk, indicating strong system detection capabilities and long-distance detection imaging capabilities. Additionally, the optical system's MTF is close to the diffraction limit, providing high-resolution imaging. Furthermore, this paper adopts 4^th、5^th lens as the compensation mirror group, realizing the design of a continuously adjustable focusing system under conditions ranging from 15 °C to 25 °C and from 1 km to infinity. The image plane position remains unchanged, so there is no need to adjust the position of the focusing plane, reducing the power consumption of the camera. The light transmitted through the beam splitter enters the active imaging system. The active imaging system adopts a common aperture beam splitter structure with integrated transceiver, which improves the coaxial stability of the system and reduces the processing and assembly requirements. The working wavelength of the active imaging system is 1 550 nm, and the wave aberration is better than 1/300λ, which can meet the requirements of laser heterodyne coherent imaging. Finally, the tolerance analysis shows that the system meets the design parameters and actual processing requirements, thus, the design is both effective and rational. In summary, the system has the advantages of high resolution, long focal length, short total length, strong thermal resistance, continuous focus adjustment, and fine imaging quality. To realize long-range tracking imaging of space debris, this design provides a reference for the realization of an integrated optical system for detection and imaging.