The morphology of submicron copper crystals was controlled by polyvinylpyrrolidone (PVP). The microscopic properties of copper crystals were characterized by SEM, XRD and laser particle size analyzer. The Materials Studio was used to combine Gibbs-Wulff"s law (crystal growth balance theory). It is speculated that the adsorption behavior of PVP molecules on the crystal faces of Cu and the morphology of copper crystals show that the copper crystals are transformed from truncated octahedron to nearly spherical after PVP modification. PVP mainly undergoes chemisorption on the crystal faces of copper. The order of adsorption is: (111)>(200)>(220). The morphology control mechanism of PVP on submicron copper crystals is that PVP forms a covalently unstable coordinating chelate with Cu, inhibiting the growth of (111), (200) and (220) crystal planes, revealing more crystal planes result in the Cu crystals becoming closer to a sphere.