Abstract: EMS technology for the thin mold has been developed,the metallurgical characteristics and the corresponding actual results of electromagnetic stirring have been measured to select specific economic and reliable process parameters.Compared the optimized internal quality effects of the slab with or without EMS,the results shows that according to the choice and optimization of process parameters to the electromagnetic stirring,central axis slab with increased equiaxed zone and improved internal quality have been produced.There is an increase of 50.5 mm on wide face on average,and the linear rate is 41%;There is an increase of 94.5 mm on narrow face on average,and the linear rate is 59%.The average level of centre crack is 0.17.The average level of middle-level crack is 0.17.The liquid core length of slab shortens 2.61 m.