Abstract: In order to guide the structure design of the Ⅰ-type sparger, the pressure oscillation characteristics of the submerged steam jet under different steam mass flow fluxes (150-500 kg/(m²·s)), pool water subcoolings (18-68 ℃), discharge hole diameters (10 mm and 16 mm) and discharge hole number (single-hole and double-hole) at the condition of atmospheric pressure were studied experimentally. The results show that the pressure oscillation intensity of the steam jet through different spargers both increases first and then decreases with the increase of steam mass flow flux or the decrease of pool water subcooling. When the discharge hole diameter or the discharge hole number increases, the minimum steam mass flow flux required to main the stable condensation decreases and the transition of flow pattern leads to the decrease of oscillation intensity. The dominant frequency of pressure oscillation is mainly affected by the subcooling degree of pool water and the discharge hole diameter for different spargers, and decreases with the decrease of the former or the increase of the latter. The influence of the discharge hole number on the dominant frequency is multiple, but the overall effect is weaker than the change of discharge hole diameter. By fitting the experimental dominant frequency, an empirical relation regarding to the pool water subcooling and discharge hole diameter was obtained, and the relative error between the prediction and the experimental values is within ±20%.