: The Taylor flow has been taken into consideration in recent decades. Many experiments have been done in this regard, although due to the difficulty of measuring, it is not possible to study some of the parameters in laboratory. So a numerical investigation can be useful. In this study, the hydrodynamic behavior and heat transfer of a Taylor air bubble flowing through a liquid in a circular microchannel with a diameter of 0.5 mm and a length of 10 mm in axial symmetry was simulated by Fluent software. Water and ethanol were used as liquid in the microchannel. The effect of fluid type, velocity and wall heat flux on the wall were investigated. The results show that the type of fluid (which changes the properties) and velocity, which are effective parameters in the capillary number and Reynolds number, change the shape of the bubbles. Increasing the capillary and Reynolds number can increas the thickness of the liquid film around the bubble and form the wave at the end of the bubble. The liquid film thickness can directly affect the heat transfer around the bubble, so that the lower the thickness, the heat transfer from the channel wall to the liquid surface occurs with lower resistance. Simulations also showed that there are rotational flows inside and around the bubble. The presence of these currents in front of the bubble causes heat transfer from the wall to the microchannel center. Such flows in the liquid film also increase the shear stress. As a result, Nusselt number increases with the velocity and heat flux on the wall. Due to the fact that the velocity increases the thickness of the liquid film, the local Nusselt number in the liquid film decreases. Keyword: Microchannel, Two Phase Flow, Taylor Bubble, Heat Transfer, Fluent