Effects of spiral magnetic field on solidification structure of the continuous casting low point alloy were investigated. It is found that the spiral magnetic field can effectively relieve the macro-segregation and cause the broke of dendrite and refinement of solidification structure. Meanwhile, effects of different magnetic fields on solidification structure were analyzed comparatively. The results reveal that, at the same electromagnetic stirring parameters, compared with rotating magnetic field, spiral magnetic field exhibits the better effect in decreasing composition segregation between the bottom and the top of ingot, refining grain size and promoting the homogenization of ingot composition. Distribution of electromagnetic force in the spiral magnetic field is more beneficial for the uniform stirring of the larger zone to effectively promote the formation of equiaxed grain. Meanwhile, orientation of grain arrangement in the spiral magnetic field is lower than that in rotating magnetic field, exhibiting the more acceptable isotropy.