It exist several strategies to mix two fluids in a micro channel. The way micro bubble vibrations influence the mixing flow is still unknown. This paper presents numerical simulations of the mixing within the micro device with and without micro bubble vibrations. A simplified model of the microchannel has been successfully employed, via using moving panels instead of sidewall-trapped bubbles oscillation. The simulation method, which exerted sinusoidal movements on the panels to approximately represent the ultrasonic vibrations of microbubbles, has been used to fully solve the Navier-Stokes equations. The comparison between simulations and previously reported experiments, in terms of flow pattern and the mixing performance within micro channel, exhibits a very good agreement. When ultrasonic vibrations of a frequency of 80 kHz and amplitude of 8 μm were applied, the mixing flow patterns have been reproduced and with a little differences comparing to the experimental results. All of these studies have revealed the mix mechanism under the micrometer scale in a certain way.