Abstract: Microfluidics control is the technique that takes advantage of the dynamic characteristics of the fluid under the micro/nano scale and makes microoperation on particles such as trapping, aggregating, self-assembling and so on. It has been a novel study filed of hybrid subjects of biology, chemistry, medicine, materials, optics, fluid and machinery. Microfluidics control driven by thermal microbubbles has excellent controllability and receives an increasing significant attention among the researchers. This paper bases on the generation mechanism of thermal microbubbles and combines the theory of thermodynamics and hydrodynamics. Using the Comsol Multiphysics 4.4 to simulate and quantitative analyze the velocity field of fluid driven by thermal microbubbles. The result turns out that the surface of thermal microbubbles exist marangoni effect and the fluid driven by it can trap and aggregate paricles in the way of vortex efficiently, which is consistent with the experimental phenomenon. In consequence, this paper explores the property of velocity field of fluid driven by thermal microbubbles, which is meaningful for improving the controllability of microfluid and the developing of microfluid control technique.