Abstract: A numerical method was developed to calculate unsteadyventilated supercavity based on the Logvinovich principle of independence ofthe cavity sections expansion. The case of the stability of unsteadyventilated supercavity was carried out. The numerical results indicated thatthe stability criterion proposed by Semenenko was available for ventilatedsupercavity. Moreover, a surface disturbance wave of the supercavity mayfirst arise and then disappear for the stable supercavity, while it will bein the self-induced oscillation for the unstable supercavity. The amplitudeof disturbance wave increased gradually to induce the periodic orquasi-periodic pulsation of supercavity.