The condensation oscillation of submerged steam was investigated theoretically and experimentally at the condensation oscillation regime. It was found that pressure oscillation frequency was consistent with the bubble oscillating frequency and there was a quasi-steady stage when bubble diameters remained constant. A thermal-hydraulic model for the condensation oscillation regime was proposed based on potential flow theory, taking into account the effects of interface condensation and translatory flow. Theoretical derivations indicated that oscillation frequencies were mainly determined by bubble diameters and translatory velocity. A force balance model was applied to the calculation of bubble diameters at quasi-steady stage, and the oscillation frequencies were predicted with the calculated diameters. Theoretical analysis and experimental results turned out that oscillation frequencies at the condensation oscillation regime decreased with the increasing steam mass flux and pool temperature. The predicted frequencies corresponded to the experimental data well with the discrepancies of +/- 21.7%. (C) 2016 Elsevier Ltd. All rights reserved.