The invention discloses a high pressure water jet and hob multi-degree-of-freedom combined rock breaking experiment device. The rock breaking experiment device comprises a rock breaking main structure, a fluid power system, a water jet pressurizing device, an electric control cabinet and an abrasive supply device, wherein the fluide power system, the water jet pressuring device, the electric control cabinet and the abrasive supply device are arranged on the two sides of the rock breaking main structure,a hob and a water jet nozzle in the rock breaking main structure are positioned on a knife seat, the fluid power system provides driving force for a hydraulic cylinder in the rock breaking main structure, high pressure water is generated and conveyed to the nozzle by the water jet pressuringdevice, and the electric control cabinet controls the fluid power system and the water jet pressuring device to work; the abrasive supply device provides abrasives for water jet ejected by the nozzle; a stone silo containing rock samples can move back and forth in the longitudinal direction and the horizontal direction;ahob seat can move up and down in the vertical direction, and the relative positions and the angles of the hob and the water jet nozzle on the knife seat are adjustable. According to the rock breaking experiment device, anindependenthigh pressure water jet rock breaking experiment or an independenthobrock breaking experimentcan be conducted, a high pressure water jet and hob multi-degree-of-freedom combined rock breaking experiment can also be conducted, and various combinations and relative parameters can be adjusted independently.