An improved modified embedded-atom method (MEAM) potential for Si was optimized. The melting point, the solid-liquid phase transformation enthalpy, the pair correlation function, the structure factor, and the bond angle distribution function of liquid Si calculated by the present potential could fit the DFT or experimental values well. The potential could be used to study the solid-liquid transformation behaviors and the liquid structure of Si. It could also be used to develop a MEAM potential for the binary Al-Si alloy.