By placing the whirling element in the nozzle body, swirling abrasive jet has been produced. The speed function of spiral groove and swirling contraction segment in inner of nozzle are analyzed. And the formulas of speed function are obtained. It is seen that movement of fluid in the spiral groove is regarded as spiral one-dimension axial symmetry, movement of fluid in the swirling contraction as spiral two-dimension axial symmetry. The swirling abrasive jet system has been established. The production method and the drilling test system of the swirling abrasive jet are introduced. The drilling mechanism of the swirling abrasive jet is analyzed. Through experiment, the effects of the whirling element structure and the jet parameters on drilling performance are studied. The results indicated that in the case of nozzle non-rotation, under the working pressure of 10 MPa, swirling abrasive jet can drill a deep hole on coal block of which Polodyakonov coefficient f is about 4, and that the diameter of the hole is 20~30 times the size of the nozzle exit diameter. So the swirling abrasive jet has a good drilling performance.