The influence of different treatment processes on microstructure and properties of Cu-Ni-Co-Si alloy were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution electron microscopy (HRTEM). The physical properties were tested as well. The results show that a large number of (Ni、Co)₂Si large phases with orthorhombic structure and few of little (Ni、Co)₂Si phase are found in the Cu-Ni-Co-Si alloy when the alloy is quenched on-line and aged treatment, which is ascribed to the low strength of the alloy. The relation curve between Vickers hardness and aging time exhibit a single peak and the electrical conductivity firstly rapid increase, then slowly raise, finally trended to stable as the aging time rise, when the Cu-Ni-Co-Si alloy is treated by solution and aging treatment and solution, cold deformation and aging treatment, respectively. Meanwhile, a lot of disc-shaped (Ni、Co)₂Si precipitates with orthorhombic structure are found in the above condition. These precipitates with orientation relationship with Cu matrix could be analyzed as 。