A planetary rotary device, comprising: a hollow cylinder block; a main shaft supported by cylinder block sealing end covers on both sides of the cylinder block; a center sun wheel drum rotatably fitted over the main shaft; an annular piston space formed by an outer circular cylindrical surface of the center sun wheel drum and an inner circular cylindrical surface of the cylinder block, wherein the annular piston space can communicate with a fluid inlet (1-1, 1-2) or outlet (1-1, 1-2) through a first set of through holes, and can communicate with a fluid outlet (1-1, 1-2) or inlet (1-1, 1-2) through a second set of through holes; and a planetary piston wheel disposed in the annular piston space in a rolling manner, wherein: both ends of the planetary piston wheel that project out of the annular piston space are connected to the main shaft, the planetary piston wheel is a circular cylindrical roller and is in contact with the outer circular cylindrical surface of the center sun wheel drum, the planetary piston wheel rolls against the outer circular cylindrical surface of the center sun wheel drum, and the outer circular cylindrical surface of the center sun wheel drum and the inner circular cylindrical surface of the cylinder block are substantially coaxial, and; the planetary rotary device further comprises an isolation structure, and the isolation structure comprises a rotary valve sheet and a rotary valve sheet spindle; the isolation structure is located between the first set of through holes and the second set of through holes in the annular piston space for isolating the annular piston space into two variable volume working spaces; and the planetary piston wheel moves along an interior of the annular piston space under the action of a difference between fluid pressures of the two variable volume working spaces, characterized in that the planetary piston wheel rolls against the inner circular cylindrical surface of the cylinder block. a hollow cylinder block; a main shaft supported by cylinder block sealing end covers on both sides of the cylinder block; a center sun wheel drum rotatably fitted over the main shaft; an annular piston space formed by an outer circular cylindrical surface of the center sun wheel drum and an inner circular cylindrical surface of the cylinder block, wherein the annular piston space can communicate with a fluid inlet (1-1, 1-2) or outlet (1-1, 1-2) through a first set of through holes, and can communicate with a fluid outlet (1-1, 1-2) or inlet (1-1, 1-2) through a second set of through holes; and a planetary piston wheel disposed in the annular piston space in a rolling manner, wherein: both ends of the planetary piston wheel that project out of the annular piston space are connected to the main shaft, the planetary piston wheel is a circular cylindrical roller and is in contact with the outer circular cylindrical surface of the center sun wheel drum, the planetary piston wheel rolls against the outer circular cylindrical surface of the center sun wheel drum, and the outer circular cylindrical surface of the center sun wheel drum and the inner circular cylindrical surface of the cylinder block are substantially coaxial, and; the planetary rotary device further comprises an isolation structure, and the isolation structure comprises a rotary valve sheet and a rotary valve sheet spindle; the isolation structure is located between the first set of through holes and the second set of through holes in the annular piston space for isolating the annular piston space into two variable volume working spaces; and the planetary piston wheel moves along an interior of the annular piston space under the action of a difference between fluid pressures of the two variable volume working spaces, characterized in that the planetary piston wheel rolls against the inner circular cylindrical surface of the cylinder block. both ends of the planetary piston wheel that project out of the annular piston space are connected to the main shaft, the planetary piston wheel is a circular cylindrical roller and is in contact with the outer circular cylindrical surface of the center sun wheel drum, the planetary piston wheel rolls against the outer circular cylindrical surface of the center sun wheel drum, and the outer circular cylindrical surface of the center sun wheel drum and the inner circular cylindrical surface of the cylinder block are substantially coaxial, and; the planetary rotary device further comprises an isolation structure, and the isolation structure comprises a rotary valve sheet and a rotary valve sheet spindle; the isolation structure is located between the first set of through holes and the second set of through holes in the annular piston space for isolating the annular piston space into two variable volume working spaces; and the planetary piston wheel moves along an interior of the annular piston space under the action of a difference between fluid pressures of the two variable volume working spaces, characterized in that the planetary piston wheel rolls against the inner circular cylindrical surface of the cylinder block.