The inflatable space antenna is gradually used in various spacecrafts because it is portable and foldaway. It is usually made of thin-film materials and has a flexible surface, so that measuring force is not tolerable in measurement process. Close-range photogrammetry is considered as an optimal solution because of its advantages of non-contact operation and fast data acquisition. To improve measuring precision, a method combining bundle adjustment algorithm and the distance constraint is presented in the paper. Two experiments under different conditions are accomplished and experiment results are compared. One experiment is completed with the distance constraint and another without. The experiment results are compared by two parameters: tightness and residuals. The measured object is an inflatable antenna with a 3.5-m diameter.