Abstract: Fuel leakage failure has occurred to a type of fuel regulators in helicopters for several times. Although many measures have been taken, such failure still takes place from time to time. In the past 2 years, such failure has taken place for about 25 times, most in winter. In the present work, the characteristics of such leakage failure were analyzed by means of statistical analysis. By analyzing the sealing mechanism, the leakage cause of the faying surface of the fuel regulators was analyzed. Analysis and verification were carried out for possible failure reasons. The results show that the leakage fault is caused by many factors.