The invention discloses a micron-sized barium sulfate micro-sphere synthesis method, and belongs to the technical field of chemical synthesis. A micron-sized barium sulfate micro-sphere is synthesizedby a reaction system comprising S2O8<2-> soluble salt, Ba<2+> soluble salt and complexing agents, and the shape of the barium sulfate micro-sphere is regulated by changing the mole ratio of the Ba<2+> soluble salt and the complexing agents, complexing temperature and the addition amount of the S2O8<2-> soluble salt. The synthesis method is simple, efficient, environmentally friendly and free frompollution, the yield of the prepared micron-sized barium sulfate micro-sphere reaches 90% or more, the particle size of the prepared micron-sized barium sulfate micro-sphere is 0.8-3 micrometers, andgranularity uniformity is good.