Disclosed are a discharge jet and a pile-plank applying the same. The discharge jet may include a discharge jet body; the body is connected with a water inlet pipe; the shape of the body is basically the same as the pile-plank; a diameter of the discharge jet is in the range of 50 mm-500 mm; water jet holes are formed in the body; the diameter of each water jet holes is in the range of 1.5 mm-15 mm; each space between adjacent water jet holes is in the range of 8 mm-80 mm; and the maximum included angle formed by the water jet holes is in the range of 30°-180°. The discharge jet and a method for driving the pile-plank into the earth by the discharge jet have the advantages of wide application range, high construction efficiency and low cost.