In order to improve the jet erosion ability, the mortar block water jet eroding experiments were carried out by using own developed self-excited oscillation nozzle under submergence conditions, and the jet erosion effects were obtained under different operating conditions. The experimental results showed that target distance had obvious effects on the erosion effect; the jet erosion volume and erosion depth firstly decreased with the chamber length increasing, then increased, and gradually decreased after reaching the peak value; the erosion volume reaches the maximum at LC=4.5 mm; and pulse jet erosion volume increases by about 37.1%~52.3% than the continuous jet.