To explore new tea germplasm for tea quality improvement, the biochemical composition and diversity were analyzed among 53 over 100-year-old wild tea plants located in 25 counties/cities of Guizhou province. High levels of biochemical diversity and variation were found. The average coefficient of variation (CV) of amino acids content, polyphenols content, caffeine content and ratio of polyphenols to amino acids (TP/AA) was 27.55% among 53 germplasms. Genetic diversity index (H') of these four indicators ranged from 1.88 to 2.08, and the mean H' was 2.00. The average CV and H' of catechins constituent in 28 wild tea germplasms was 37.10% and 1.82, respevtively. TP/AA in 13 germplasms, 28 germplasms and 12 germplasms was less than eight, 8～15, greater than 15, respevtively. By means of cluster analysis, when the Euclidean distance was about 15, 53 resources were clustered into three groups, without independent group. Five high polyphenols germplasms, one potential elite germplasm and 20 special germplasms were preliminarily selected from 53 wild tea plants.