High mountain tea(HT)is an important resource for high quality tea because of its superior ecological environment and rich contents. In this study, we used sensory evaluation, gas chromatography–mass spectrometry(GC-MS), liquid chromatography-mass spectrometry(LC-MS), flavor activity value and risk factors to characterize the flavor (aroma and taste) and safety (heavy metals and pesticide residues) characteristics of HT, and then combined with the production process and environmental conditions to explore the reasons for its quality formation. The results showed that, the aroma sensory characteristics of HT were tender and green, accompanied by sweet and slight chestnut. 8 aroma compounds were identified as the important contributing substances to aroma characteristics and the high ratio of " green substances " and "chestnut substances " was the main reason for its unique aroma characteristics. The taste sensory characteristics of HT were high in freshness and sweetness, low in bitterness and astringency. High content of soluble sugar, non ester catechins, sweet free amino acids and low content of caffeine and tea polyphenols are the main reasons for its taste characteristics. Low temperature stress is the most fundamental reason for the formation of flavor characteristics of HT. In addition, the pollution risks of HT of 5 heavy metals and 50 pesticide residues are all less than 1. The complex ecosystem and low level of chemical control are the main reasons for the high safety quality of HT. All in all, these findings enable us to have a more comprehensive understanding of the quality characteristics and formation reasons of HT.