Abstract: The engine intake hose of a heavy truck was cracked in many places after 6 months of use. The cracking causes of intake hose were analyzed by means of macro observation, steel wire physical and chemical test, steel wire fracture analysis, wall thickness measurement of intake hose and withstand voltage test. The results show that the degumming on the surface of the wrapping layer of the intake hose caused the stress corrosion fracture of the hose steel wire, and the fractured steel wire caused the bulge on the hose wall. Some sharp fractures pierced the hose to form the open breakage, and further tore and expanded, which eventually led to the cracking failure of the hose.