The invention discloses ultrahigh pressure water jet wall-climbing derusting complete set equipment and a process thereof. High-pressure water is output from an ultrahigh pressure pump, is output to the cleaning surface through an ultrahigh pressure rotary spray head connected with an ultrahigh pressure hose and carries out ultrahigh pressure water jet cleaning on the cleaning surface; the outside of the rotary spray head is sealed and provided with a cover shell; the edge of the cover shell is provided with an elastic material; the cover shell is communicated with a vacuum system; in the cleaning process, synchronous vacuum pumping is carried out on the cleaning surface to absorb wastewater in the cover shell and realize vacuum wall attachment; the equipment is also provided with a wall-climbing robot for driving the rotary spray head and the cover shell to move on the cleaning surface according to an instruction and carry out large-area derusting operation on the cleaning surface; the working parameters of ultrahigh pressure water jet cleaning comprises the following: the water pressure is between 220 and 250 MPa, the flow rate is less than 30 L/min; and the vacuum degree of thecover shell is about 0.06MPa+-5percent. A rust layer is peeled off through water jet; rust chips and waste slag are whirled away through a vacuum flow; and the operated surface is dried in time through a temperature field. Therefore, the operated surface is removed with rust through water and is dried; and the rust is removed and is not returned.