A laboratory study was carried out, using Pb-15 wt.% Sn alloy on self-made apparatus, to determine the solidification behavior of the semi-solid slurry with the solid fraction beyond 0.6. It is found that the solid-liquid separation is obvious in the samples with the solid fraction beyond 0.6. According to this character of semi-solid processing, a kind of single-crystal powder coated with Pb-Sn eutectic was made during continuous stirring and cooling processes. The analysis and discussion indicated that this approach can reduce the content of oxide and impurity in the powder.