The microstructure evolution and element segregation of semi-solid ZCuSn10P1 copper alloy slurry prepared by large plastic deformation strain-induced melting activation method were studied, and the influence of isothermal treatment time on slurry characteristics was analyzed. The results show that the average grain size increases from 21.1 μm at 1 min to 68.8 μm at 10 min with the increase in isothermal treatment time at 900 ℃. The shape factor firstly increases and then decreases, from 0.31 at 1 min to 0.76 at 5 min, and then decreases to 0.56 at 10 min. The liquid phase ratio increases from 3.1% at 1 min to 9.3% at 5 min and remains stable. The diffusion layer thickness of Tin increases from 0.422 μm at 1 min to 1.704 μm at 10 min, and the content of Tin in liquid film and grain core is exponentially related to the isothermal time. The optimum isothermal treatment condition is 900 ℃ for 5 min. At this time, the average grain size, shape factor and liquid island size of the semi-solid copper alloy are 29.6 μm, 0.76 and 3.1 μm respectively. The average grain size and shape factor of the semi-solid copper alloy prepared by conventional strain-induced melting activation method are reduced by 58.9% and increased by 28.8%, respectively. The liquid island size is reduced by 31.1%, and the segregation of tin element is weakened.