This study focuses on the body shape of Vietnamese women, collected from large-scale measurement data, to establish a bra size system for mature Vietnamese women aged 18 to 55. Measurement data was collected from 1100 subjects using a 3D scanner. During the data collecting process, 18 measurements at the chest area were classified and used for the research and analysis. Data analysis is performed by the Principal Component Analysis (PCA) method and Numerical Analysis. Mean and median values are used to understand the central tendency of sizing charts. Standard deviation is leveraged to derive size categories, intervals and separate the outliers. Two size-matching solutions are implemented to find the optimal sizing system. The result found a 26 sizes bra system which is a combination of 5 band sizes and 6 cup sizes, with a response rate of 98.27% based on the primary dimensions of bust girth and underbust girth. The study's results were compared with the bra size systems of some countries in Asia and around the world, showing that differences in body shape have led to differences in the systems. the number of sizes. The ultimate goal of this research is to systematically establish a data database with local characteristics and significance that will contribute to sustainable development in academic research, industrial production, application, commercial activities, and service design in the future. The results of this study are meaningful for bra manufacturers in the Vietnamese market and for women in selecting suitable bras for their somatotype.