Traditional casting usually solidifies one homogeneous liquid by removing heat from liquid surface, by which the microstructure solely depends on the heat removal rate for the given alloy composition. The newly developed two-liquid composite simultaneous casting concept raises an alternative to control microstructure. The concept introduces the solidification while mixing technique so that the microstructure depends not only on the heat-removing from liquid surface but also the heat transfer from one liquid to another. The paper reports the experimental validation of the concept by two-liquid casting of Sn-Pb alloys. Reduced grain size, increased microhardness, rougher and more fractal grain surfaces are observed for the alloy solidified by two-liquid casting in comparison of the microstructure obtained by conventional solidification techniques.