The invention belongs to the technical field of continuous casting and semi-continuous casting, and particularly relates to a side spiral electromagnetic stirring device which comprises a box body, amagnet yoke fixing plate arranged in the box body, a magnet yoke connected with the magnet yoke fixing plate, a coil wound outside the magnet yoke, a box body cover fixed at the top of the box body through a fixing bolt, a power supply device and a cooling device arranged at the side part of the box body, and is characterized in that the longitudinal inclination angle of a magnet yoke body rangesfrom -80 degrees to 80 degrees, the transverse inclination angle of the magnet yoke body ranges from -40 degrees to 40 degrees, the coil winding is arranged on the obliquely cut magnet yoke; and the end surface of the magnet yoke is parallel to the wall surface of the magnet yoke fixing plate. According to the side spiral electromagnetic stirring device provided by the invention, the flowing rangeof a circulation can be expanded, the flowability of molten metal in a casting blank is effectively improved, the grain structure is refined, the element segregation degree is reduced, metal feedingat the solidification tail end is promoted, and particularly, molten steel flowing, heat transfer solidification, solute segregation and other behaviors in the solidification process of the large-section continuous casting blank are directly affected, so that the solidification quality of a large-section casting blank core is improved.