Abstract: Currently, imported rotary jet heads occupy the market of mechanical cleaning of underground oil storage tanks in service stations in China. In this regard, an experimental prototype of rotary jet head is developed by referring the technical specifications of foreign products. Its key internal components such as hydraulic impeller, planetary gear reducer and nozzles are designed and calculated. Revolution and rotation of nozzles are realized under the driving of rotation of output shaft and bevel gears. Using the Pro/E software for virtual assembling and motion simulation of the rotary jet head, it turns out that the path of any point at the outlet of the nozzle is a spatial spherical enveloping surface. The result of the prototype operating experiment shows that the jet radius of nozzle can be up to 5-6 m when the inlet water pressure is about 1.0 MPa, which proves that the structural design of the rotary jet head is feasible and rational.