To clarify the genetic diversity of tea plant germplasm resources in Wangcang county， Sichuan province， and identify potential superior germplasms for new cultivar breeding， this study utilized a self-developed liquid-phase functional chip for tea plant to genotype 76252 SNP loci in 136 accessions. Combined with biochemical component detection and organoleptic evaluation， the genetic structure and quality characteristics of these local germplasms were comprehensively analyzed. Genome-wide association studies were further conducted to identify SNP loci and candidate genes significantly associated with quality traits. The results show that the tea plant germplasm resources in Wangcang county exhibit rich diversity and distinct regional characteristics. Among them， the ancient tea plant population from Daliang town is identified as a transitional type， rich in esterified catechins—especially epigallocatechin gallate. And the baked green tea produced from these plants demonstrates excellent quality， with a generally refreshing and high-aromatic profile featuring floral （or fruity） notes， and a taste characterized by sweetness， mellowness， and freshness. Based on 40326 core SNP loci detected， four candidate genes （γ-CA1， TPR5， MYB94， and UGT85A1） significantly correlated with the content of amino acids， tea polyphenols， and epigallocatechin gallate were identified. These results provide a theoretical foundation for the future development and utilization of tea plant germplasm resources in Wangcang.