Abstract: Influence of thermal physical properties variation of de-ionized water with different heating flux on heat transfer characteristics in staggered arranged micro-cylinder-groups were experimentally and numerically investigated. The integrated micro-cylinder-group chip was heated by heating elements and the Nusseh number(Nu) was obtained by measuring temperatures in micro-cylinder-group chip. Besides, a 3-D numerical model considering the roughness effect on inner surfaces of micro-cylinder-groups was used to simulate the temperature fields and heat transfer characteristics with different heating flux. By comparing the calculation results with the experimental results, it was found that the thermal physical properties of working fluid changed with the temperature, and this variation brought out apparent influence on heat transfer characteristics in micro-cylinder-groups. In addition, the heat transfer coefficient was enhanced by increasing the heating flux, especially at low Reynolds number (Re). Different affecting coefficients were defined to quantitatively analyze the influence of thermal physical properties, and it was found that the affecting coefficient of viscosity was nearly 10% , which was much higher than that of the other properties.