Camellia Sinensis var. assamica in Hainan serves as a representative and critical local germplasm resource in Hainan, playing a pivotal role in the development of the Hainan tea industry. To further explore its biological resources and economic value, 50 samples of Camellia Sinensis var. assamica germplasm were analyzed based on five quality traits: water extract, caffeine, theanine, tea polyphenols, and the phenol-ammonia ratio. The results indicate that the germplasm resources of Camellia Sinensis var. assamica possess rich genetic diversity. The average coefficient of variation for the five quality traits was 16.87%, with an average diversity index of 3.984. Caffeine exhibited the highest coefficient of variation at 47.44%, while the phenol-ammonia ratio had the lowest at 0.22%. Correlation analysis revealed that the water extract was positively correlated with theanine, tea polyphenols, and the phenol-ammonia ratio, whereas theanine showed negative correlations with tea polyphenols and the phenol-ammonia ratio. Principal component analysis identified two principal components, accounting for a cumulative contribution rate of 79.12%, which reflect key indicators of basic quality and flavor specificity. Suitability analysis demonstrated that the phenol-ammonia ratio of Camellia Sinensis var. assamica is less than 8, making it suitable for green tea production. Notably, the Wanning region is characterized by high theanine content and a low phenol-ammonia ratio, ideal for producing high-quality fresh green tea. Wuzhishan tea exhibits high polyphenol content, showing great potential for black tea and dark tea production. Lingshui Mountain tea has a high caffeine content, suitable for oolong tea development. Cluster analysis grouped the germplasm into four clusters, with the second and fourth clusters (medium and lower-middle levels) comprising 76%. The first cluster (high-content group) and the third cluster (low-content group) can serve as complementary materials for directional breeding. To sum up, Camellia Sinensis var. assamica exhibits significant potential in tea variety breeding, processing technology optimization, and the development of distinctive tea products. In future research, it is essential to integrate genetic marker analysis to further elucidate the genetic basis of its quality traits. Additionally, the quality of tea production should be rigorously evaluated through sensory assessment to ensure precise resource utilization and thereby promote the high-quality development of the Hainan tea industry.