To a high resolution digital camera which works in visible light and is on the space-based platform flying in 500 km orbit, analyzed the principle of image acquisition, established the collinear equation and target location model from the system measured the pose of camera and single image without control points, and researched the method to calculate the geographic coordinate of target point. Analyzed the consisted factors of target location accuracy, and generated the formula for calculating target location accuracy based on the accuracy theory. For the cameras working in this mode, gave the elements of orientation and the parameters of camera, then obtained the target location accuracy is 16.1 meter through the simulation analysis to the model. The analysis to the target location accuracy provides a theoretical base for the practical use of the space camera. Analyzed the impact of the camera parameters and operation mode on the location accuracy, and put forward some measures to improve the target location accuracy. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.