The invention discloses a micro-abrasive material water-jet cutting head apparatus, and relates to the field of mechanical processing equipment, particularly to a micro-abrasive material water-jet cutting head apparatus, which comprises a material storage tank, a mixing chamber and a spraying head, wherein a piston is arranged in the material storage tank, the material storage tank is divided into a compressed air cavity and a slurry abrasive material cavity through the piston, the lower end of the material storage tank is connected with a material feeding soft pipe, the material feeding soft pipe is connected with the mixing chamber through a screw pump shell, a material feeding screw connected with a stepper motor is arranged in the screw pump shell, the mixing chamber is arranged in the spraying head, the upper end of the spraying head is provided with a high pressure water chamber, the lower end of the high pressure water chamber is connected with the mixing chamber through a water spraying nozzle, and the lower end of the mixing chamber is provided with a mixed material spraying pipe. According to the present invention, the screw is adopted to perform the active material feeding, such that the material feeding reliability is high, the suction is uniform, the material feeding flow can be controlled, and the abrasive material conveying system failure caused by directly entering of the high temperature water into the abrasive material tank after the clogging of the spraying head can be prevented.