Abstract: A vehicle cracked in the HST2425 titanium suspension assembly while driving. The cracking causes of the suspension assembly were analyzed by macro observation, scanning electron microscopy analysis, chemical composition analysis, mechanics performance test and metallographic examination. The results show that during the die forging process of titanium alloy suspension assembly, irregular microcracks at a low temperature were produced due to low forging temperature. Under the action of wheel tension, the cracks on the outer surface of the titanium alloy suspension assembly die forging further expanded and cracked.