Noni fruit is rich in bioactive substances such as polyphenols and flavonoids, and its processing techniques directly affect the retention rate of functional components and quality stability. Using wild Noni fruit from Hainan as the research subject, this paper employed three processing techniques: natural sun-drying, hot-air drying, and vacuum freeze-drying. The retention rates of polyphenols, flavonoids, and enzyme activities such as SOD were analyzed, and the antioxidant activity, nutritional quality, and storage stability of products from different processes were compared. The research results indicate that vacuum freeze-drying yielded the highest retention rate of active components and the best product quality stability, providing a reference for the industrial processing of Noni fruit.