The mixing process of static mixer is conducted by a series of different sizes of mixing units which installed in the hollow pipe. Since the function of the mixing units, the fluid sometimes turn left, sometimes turn right, changing the flow direction, not only pushing the central fluid towards the periphery, also pushing the surrounding fluid towards the center, resulting in a good radial mixing. This mixer doesn't have moving parts, relying on the special structure of units and fluid movement, so that the immiscible fluid dispersed and mixed with each other.