Abstract: A sphere precision machining device and a machining method comprise a cavity, an abrasive grain stream, and a circulation device. The cavity holds the workpiece, and comprises two hollow hemispheres, each of said two hemispheres being provided with a main flow channel. Said main flow channel is connected to the cavity. One end of the main flow path of each of the two said hemispheres is connected to a circulating means by which a stream of abrasive grains is made to grind the workpiece. A plurality of main flow channels are disposed homogeneously inside the hemisphere, each of said main flow channels being provided with a plurality of branch flow channels connected to the cavity, said branch flow channels tapering in the flow direction. The present disclosure uses the difference in abrasive grain flow pressure on the surface of the workpiece to achieve precision machining.