The invention discloses a specific crystallizer casting powder for sulphur free-cutting steel and production method thereof, mass percents of chemical components thereof are as follows: 29-35% of CaO, 25-30% of Sio2, 2-5% of MgO, 3-5% of Al2O3, 2-6% of Fe2O3, 5-11% of NaO?, 0-2% of Li2O, 5-9% of CaF2?, 0-5% of MnO, 0.5-2.0% of Al grey, 0-2% of B2O3, 5-11% of solid carbon, and allowance is building material adhesive and water. The sulphur free-cutting steel has low high-temperature strength and high crack sensitivity, and the casting powder should have properly high basicity. Basicity of a slag is improved, so that diffusion velocity is accelerated, and absorption of impurities in molten steel is benefited. So, improvement of basicity is an effective means for improving absorption of the impurities and control of surface longitudinal crack.