In a direct contact system,steam is ejected to heat water through an ejector.During the process of ejection,the noise is aroused due to the volume change of bubbles,and the turbulent mixing between steam and adjacent water.To solve this problem,experiment was done under variant water temperature and steam flux using ejectors with different structures.The results show that the jet noise is mainly affected by water temperature and steam flux,between them the water temperature is the main factor,and there exists partially a linear correlation between steam flux and A weighted sound level.