Considering the advantages of the unit vector method, a method is proposed for the initial orbit determination (IOD) of space targets using a camera array. The novel condition equations and details regarding the process are given. A space target is tracked by a custom-built camera array system, and the data from a 5-min long observation at 25-Hz frame rate are processed and calculated. The IOD results for the space target at different observation times are obtained, and their accuracy is analyzed by using the measurement accuracy of the orbital semi-major axis as the main indicator. The experimental results show that the proposed method effectively reduces the IOD error and enhances the IOD stability.