The invention presents a novel polyimide-based thin film self-assembly technology, including five process steps described as follows: (1) deposits a sacrificial layer and a low-stress microstructure layer on a silicon substrate; (2) patterns and etches the low-stress microstructure layer to provide a stationary part and a movable part of the microstructure; (3) coats a photosensitive polyimide thin film as elastic joint of the microstructure layer and defines the shape by using photolithography technique; (4) releases the sacrificial layer beneath the movable part of microstructure layer by wet etching; (5) lastly proceeds the reflow process of polyimide to result in the contraction of the elastic joint further to rotate and lift the movable part in completion of the self-assembly of the microstructure. As the invention can be extensively applied to a myriad of miniaturizing industries, it can solve all the drawbacks of the prior art manufacturing process and miniaturization.