An experimental study was carried out on the pressure oscillation caused by direct contact condensation (DCC) of steam jet in water. The published researches on pressure oscillation caused by DCC were generally performed in large space pools. However, the condensation oscillation characteristics of steam jet in water flow in a confined space have not been fully understood yet. During this experiment, the steam and water were introduced into a confined channel at the same side. The dynamic pressure signals were measured without interfering the flow field. The behavior of the interface was captured by a high speed camera. The main inlet parameters, i.e. steam mass flux, water Reynolds number and water temperature were tested in the range of 150-600 kg/(m(2) s), 78,000-172,000 and 25-60 degrees C, respectively. The results indicated that flow patterns were determined by these three inlet parameters. According to the structure and behavior of the interface, the flow patterns under various test conditions could be divided to unstable and stable types. As flow patterns transformed from stable to unstable, the pressure oscillation intensity increased sharply. The dominant frequency for subsonic steam jet condensation oscillation in water flow was in the range of 168-1177 Hz. The frequency increased with the increase of water Reynolds number, but decreased with the increase of steam mass flux and water temperature. Moreover, a correlation for the dominant frequency was given as a function of the condensation driving potential, steam mass flux, Weber number and water Reynolds number. The predicted values agreed well with the present experimental values at the maximum deviation of 20%. (C) 2016 Elsevier Ltd. All rights reserved.