The composition of a kind of high acid apple from Xinjiang,China,namely Hongxun Ⅰ ( red flesh) ,was determined,finding that the high acid apple is of a titratable acidity of 1. 31%,a total phenolics and anthocyanins content in an order of peel ＞ pomace ＞ whole fruit ( with a total phenolics content of ( 2026. 88 ±28. 30) mg /kg and a total anthocyanins content of ( 244. 92 ± 13. 88) mg /kg) ＞ flesh.Then,ten phenolic compounds including chlorogenic acid,phlorizin,epicatechin,ferulic acid,myricetin,catechins,vanillic acid,p-coumaric acid,rutin and caffeic acid were indentified by means of high-performance liquid chromatography,finding that the high acid apple is rich in chlorogenic acid ( ( 391. 19 ± 18. 37) mg /kg) ,epicatechin ( ( 698. 82 ± 17. 21) mg /kg) and catechins ( ( 570. 30 ± 9. 21) mg /kg) .Moreover,the antioxidant and anti-hemolysis activities of the high acid apple were determined by means of DPPH radical scavenging activity assay,oxygen radical absorption capacity assay and AAPH-induced oxidative damage human erythrocytes model,finding that the peel,flesh,pomace and whole fruit of the high acid apple all exhibit excellent antioxidant activity and that the anti-hemolysis activities are indicative of the following order: peel ＞ pomace ＞ whole fruit ＞ flesh.All these above-mentioned statements indicate that,as a valuable product,high acid apple is worth processing and developing.