Abstract: 【Objective】 To understand the relationship between endogenous hormones, carbohydrates and cell metabolic enzyme activity in fruit cracking. 【Methods】 Easy to crack varieties 'fucuimi' was taken as the testing material to conduct field experiment in half red stage of dehiscent fruit high crack occurrence periods, which aimed to study dehiscent fruit and normal fruit peel SOD, POD, PPO, cellulase and pectinase, cellulose, hemicellulose, pectin substances and endogenous hormones contents, and fruit of sucrose, starch, soluble total sugar, reducing sugar, glucose, fructose, crestor titration acid and the content of endogenous hormones were determined. 【Result】 The activity of POD and SOD in the peel of cracked fruit was significantly higher than that of non-cracked fruit and normal fruit.; The content of hemicellulose, WSP and ISP in the non-cracked pericarp was significantly higher than that in the cracked pericarp, and the content of CSP in the non-cracked pericarp was significantly higher than that in the cracked pericarp; The total soluble sugar, sucrose and starch contents in the pulp of the cracked fruit were significantly higher than those in the non-cracked fruit; The content of GA₃ in peel of non-cracked fruit was significantly higher than that peel of cracked fruit; The content of IAA in the pulp of the cracked fruit was significantly higher than that of the non-cracked fruit. 【Conclusion】 Changes of hemicellulose content WSP and ISP content as well as POD activity and SOD activity in the peel of the cracked fruit to change the structure of the peel and the properties of the peel, combined with sucrose and soluble total sugar content in the pulp of the change and the endogenous hormone IAA content in the fruit pulp, fruit growth caused by unbalanced and the changes of fruit internal osmotic potential, This causes the fruit to grow incongruously with the skin causing the fruit to crack.