The effect of homogenizing annealing and thermo-mechanical treatment processes on microstructure and property of Cu-15Ni-8Sn-1.0Zn-0.8Al-0.2Si alloy was investigated using mechanical property test, electrical conductivity measurement, optical microscopy, scanning electron microscopy and transmission electron microscopy. The alloy ingot was two-stage homogenizing annealing treated at 830 ℃/2h+850 ℃/2h, hot rolled by 70%, then solution treated at 850 ℃ for 1 h, followed by 60% cold-rolling deformation and aging treatment at 400 ℃ and 450 ℃ respectively. After aged at 450 ℃ for 30 min, the hardness was 378HV, electrical conductivity was 8.0% IACS, tensile strength was 1144MPa, yield strength was 1098MPa, elongation percentage was 3.29%. During aging at 400 ℃ for 1 h, the hardness was 390 HV, electrical conductivity was 7.4% IACS, tensile strength was 1164 MPa, yield strength was 1112 MPa, elongation percentage was 3.05%. The combined effects of spinodal decomposition strengthening, precipitation strengthening and substructure strengthening were the mainly strengthening mechanism in alloy. Meanwhile, since the precipitation of solute atoms, the solid solubility of matrix was reduced, and the electrical conductivity of alloy was improved. After two-stage homogenizing annealing treatment, the microstructure of alloy was homogeneous equiaxed grain. It was found that spinodal decomposition and L12 ordering (β-Ni3Sn) appeared in the alloy during aging at 400 ℃ for 1h. The crystal orientation relationships between copper matrix and β-Ni3Sn precipitates were determined as: ‖ , ‖ ; ‖ , ‖ .