<p>For developing a process of preparing high-quality semi-solid billets, as-cast tin bronze billets were separately pre-annealed at 700&#xa0;°C for 1, 2, 4, 6, and 8 hours respectively. The annealed billets were subsequently cold-rolled and isothermally treated to produce semi-solid slurries. Optical microscopy (OM), scanning electron microscopy (SEM), x-ray diffractometer (XRD), electron probe x-ray micro-analyzer (EPMA), and transmission electron microscopy (TEM) were used to explore the microstructure evolution and elemental segregation behavior of semi-solid ZCuSn10P1 slurries. The results revealed that after pre-annealing, the Cu₄₁Sn₁₁ (<i>δ</i>) phase in the as-cast billet was deconstructed, and Sn dissolved into the α-Cu matrix. The amount of Sn in α-Cu grains in the semi-solid billet steadily increases with longer pre-annealing times, leading to improved intergranular segregation of Sn. When the pre-annealing time exceeds 2&#xa0;h, the increase in the Sn content is not apparent. The mean grain size increases with pre-annealing time, whereas the roundness (the ratio between the areas of a grain and that of a circle with a diameter equal to the grain’s length) decreases. The optimal process parameters are achieved through pre-annealing at 700&#xa0;°C for 2&#xa0;h, resulting in a semi-solid microstructure with an average grain size of 74.1&#xa0;μm and a shape factor of 0.7.</p>