In recent years, nano-sized barium sulfate has a much broader market prospect for its wider and wider application. But compared with common barium sulfate, nano-sized barium sulfate has some disadvantages. Because of its small particle size, large specific surface area, high cohesive energy and unsteady state of thermodynamics, nano-sized barium sulfate is easy to aggregate and cake, influencing the dispersion. If dispersion is reduced, the value of nano-sized barium sulfate is decreased. In the industrial application, nano-sized barium sulfate usually disperses in liquid medium where it is easy to coagulate, aggregate and form secondary particle. Thus the particle size is larger and nano-particle finally lost its peculiar function when it is used. At present, there is no article which reported condition experiment on the dispersion of nano-sized barium sulfate suspension. So, the author studied the dispersion behavior of nano barium sulfate in liquid medium by means of adding dispersing agents and ultrasound, got nano barium sulfate fluid with good suspension stability. Thus, the dispersity of nano barium sulfate is improved.