Panoramic cameras, with their broad field of view and rich environmental information, are often employed for visual guidance and positioning of extravehicular space robots. To provide high-precision structural parameters for panoramic vision positioning, this paper proposes a calibration method for the structural parameters of a multilens combined panoramic camera system. High-precision photogrammetric measurements of a constructed calibration field are taken, and by utilizing the coordinates of markers in the world coordinate system and their corresponding image plane coordinates, the absolute poses of four cameras are determined. Subsequently, constraints are established based on the relationship between the origin of the world coordinate system and the positions of each camera, to solve for the pose transformation relationships between the reference camera and the other three cameras, which represent the system’s structural parameters. Experimental results show that the standard deviation of the image plane re-projection error of markers for all cameras in the panoramic camera system is 0.827 5 μm (1/9 Pixel), with a relative positioning error for all structural parameters of 1.03 mm, and a relative angle calibration error of 0.03 rad. This method can meet the high-precision requirements of structural parameters for the panoramic vision positioning of extravehicular space robots.