The impurities Al,Ca,Ti,B,P etc in metallurgical grade silicon(MG-Si)can be effectively removed by refining using molten slag based CaO-SiO_2,and it is especially effective for boron removal.The experiments of boron removal were studied using CaO-SiO_2 binary slag in induction furnace.The results showed that the distribution coefficient of boron(L_B)between slag and silicon increased with more proportion of CaO/SiO_2(mass%).It was advantaged to boron removal for higher basicity of slag,so the boron in MG-Si was reduced from 18ppmw to 1.4ppmw with the addition of Li_2O and K_2O to Ca0-SiO_2 slag.The proportion of SiO_2 in slag affected the oxidizing capacity of slag,which reduced the efficiency of boron removal.