Abstract: Spin coating can be controlled by a few parameters such as the rotating speed and solid density to yield a well-defined film, which can often be used to create highly uniform coatings. Solid pyromellitic dianhydride and 4,4-oxydianiline were added to N,N-dimethyl acetamide to form polypyromellitamic acid solution and films were cast from the solution.The paper focuses on fabrication of high quality polyimide on the basis of experiments especially for uniformity film thickness and good film properties. It implicates that the rotating speed and fluid density have strong effects on the film thickness. Under suitable experiment condition polyimide film can be fabricated with suitable thickness. The film thickness fluctuation is no more than 5％, and the film surface finish 0.3～0.4 nm. The ten