Abstract: Cavitation flow images are much used in the study of cavitation phenomena.A cavitation flow image program is developed,introducing many image processing functions different from the traditional ones and overcomes restrictions in commercial softwares.By employing the program,the outline,boundary,gray level and area of the flow images around a super-cavitation hydrofoil in the cavitation zone can be extracted successfully.Moreover,the evolutional period of cavitation can be estimated based on image gray,so that the cavity configuration and transformation can be studied quantitatively.The reliability and frequency of the processed cavitation are improved in order to understand the mechanism of cavitation flow.