Automotive stabilizer-bar is an important part of a suspension system, which is used to prevent the car body from rolling when taking sharp turns. The rear stabilizer-bar of a testing vehicle ruptured when running on the enhanced road until 9,110 km. To make a contrast, three rear stabilizer-bars of such vehicle model were tested on the torsional test bench, which ruptured when load cycle reached 14,000-17,000 cycles. In order to associate the road test with the bench test, strain gauges were utilized to collect the load spectrum of rear stabilizer-bars from road test and bench test. Equivalent life was calculated using the TecWare software. For the sake of identifying the root cause of the rupture and proposing the quality improvement, different kinds of analysis such as force, rupture feature, chemical composition, hardness and metallographic structure are performed in this paper. The test result shows that high-temperature processing leads to a 33 per cent decrease in surface hardness, which results in a significant reduction in the fatigue strength.