The grain refinement and macrosegregation control of GCr15 bearing steel were investigated under a type of rarelyused electromagnetic stirring,vertical electromagnetic stirring( V-EMS),in continuous casting. V-EMS can create an upward electromagnetic force and generate longitudinal loop convection,which enables the better mixing of the upper part with the lower part of the liquid steel. The results showed that applying V-EMS can enlarge the region of the equiaxed grain,decrease the secondary dendrite arm spacing( SDAS) and reduce the segregation of both carbon and sulfur. After applying V-EMS,liquid steel with a high solute concentration is brought to the dendrite tips,making the dendrite arms partially melt. The length of the dendrite fragment is approximately 1. 8 mm,10 to 12 times the SDAS. Upon increasing the amount of cooling water from 2. 0 to 3. 5 m~3/h,the dendrite fragments exhibit an obvious aggregation following V-EMS. Finally,a criterion for dendrite fragmentation under VEMS was derived based on the dendrite fragmentation theory of Campanella et al. The grain refinement and macrosegregation control of GCr15 bearing steel were investigated under a type of rarely used electromagnetic stirring, vertical electromagnetic stirring (V-EMS), in continuous casting. V-EMS can create an upward electromagnetic force and generate longitudinal loop convection, which enables the better mixing of the upper part with the lower part of the liquid steel. The results was that applying V-EMS can enlarge the region of the equiaxed grain, decrease the secondary dendrite arm spacing (SDAS) and reduce the segregation of both carbon and After applying V-EMS, liquid steel with a high solute concentration is brought to the dendrite tips, making the dendrite fragments partially melt. The length of the dendrite fragments is approximately 1. 8 mm, 10 to 12 times the SDAS. Upon increasing the amount of cooling water from 2. 0 to 3. 5 m ~ 3 / h, the dendrite fragments exhibit an obvious aggregation following V-EMS. Finally, a criterion for dendrite fragmentation under VEM S was derived based on the dendrite fragmentation theory of Campanella et al.