Abstract: Old trees were regarded as “green national treasures” and “living cultural relics”. How long does the longevity of old trees last? What is the difference in longevity among tree species of different taxonomic positions? These issues are currently unclear. In response to these issues, the authors collected global tree ring data and sorted out the longevity of 390 tree species in 108 genera from 44 families. Among these taxa, the longevity range of gymnosperms is 64−4 900 years, with an average of 788 years. The longevity range of angiosperm trees is 40−4 021 years, with an average of 537 years. The longevity of trees in seed plants can be divided into four levels. Level Ⅰ, exceptionally long longevity, ≥1 000 years. Level Ⅱ, long longevity, 500−999 years. Level Ⅲ, medium longevity, 100～499 years. Level Ⅳ, short longevity, <100 years. The longevity of seed plants shows evident taxonomic differences, with the top 10 genera of gymnosperms having the longest longevity being Pinus L.(4 900 years), Cupressus L.(4 021 years), Taxus L.(4 021 years), Fitzroya Hook. f. ex Lindl.（3 622years）, Chamaecyparis Spach(3 500 years), Sequoiadendron J. Buchholz(3 266 years), Cryptomeria D. Don(3 021 years), Juniperus L.(2 868 years), Taxodium Rich.(2 624years) and Sequoia Endl.(2 220 years). The top 10 genera of angiosperms with the longest lifespan are Olea L.(4 021 years), Cariniana Casar.(3 021 years), Castanea Mill.(3 021 years), Ficus L.(2 217 years), Adansonia L.(2 071 years), Platanus L.(2 071 years), Cinnamomum Fabr.(1 971 years), Cercidiphyllum Siebold & Zucc.(1 971 years), Prunus L.(1 921 years) and Quercus L.(1 721 years). The data edited in this article will provide references for the study on tree aging process, longevity mechanism, and protection technology.