Abstract: The bonding quality of polyimide (PI) films on the solar array battery substrate of spacecraft directly affects the working life of the substrate. To effectively, quickly, and accurately detect the bonding quality of PI films, the typical defects on PI films such as microscale and non-explicit debonding, bubbles, and protrusions were identified by thermal cycling and thermal vacuum environmental tests. A visual inspection method based on polarization imaging technology was utilized to conduct orthogonal experiments on four sets of prepared samples, by which the typical defects and their specific demensions on bonding areas of PI films were recognized accurately. The experimental results indicate that the technique is effective in detecting the bonding defects of PI films.