In recent years, the advantages of multi-sensor integration are gradually highlighted. In this paper, an integrated imaging system (IIS) of airborne synthetic aperture radar (SAR) and visible light camera (VLC) based on common aperture antenna is designed to meet the mission requirement of acquiring visible light and SAR images simultaneously. The IIS adopts the coaxial scheme, its structure is simple and compact, and is more suitable for airborne platform. In this paper, a parameter design method of IIS based on common aperture antenna is proposed. After the system parameters design, the imaging performance of IIS is analyzed by simulation. The results show that the system parameters are designed reasonably and the imaging performance meets the mission requirement. The designed IIS can realize the visible and Ka-band (30 GHz) dual-band imaging. Under the condition of 20 km altitude, the imaging resolutions of VLC and SAR are higher than 0.2 m and 0.3 m respectively, the field of view of VLC is 1.46°, and the swath length of SAR is greater than 870 m.