This paper investigates the effect of channel shape on the micro-channel and slot-jet module with the realizable k-epsilon turbulent model. Cooling performance of three channels with a same cross-section area but different shapes (rectangular, trapezoid and circular) are comparatively discussed. The hybrid module with circular channel has the maximum pressure drop at the same flow rate. While the hybrid module with trapezoid channel achieves the best cooling performance. Its superiority in the cooling performance enlarges with the heat flux rising and the pump power increasing, as compared with the other two hybrid modules. The local thermal resistance in the trapezoid channel exhibits peak-shape distribution, which is very different from the other two shapes channel. In addition, the cooling performance of the trapezoid channel module can be further improved by the optimization of the three geometric parameters (channel height, channel bottom width, and channel corner angle). When the optimal value for the three parameters is respectively adopted, the temperature on the bottom surface of the module can be reduced by 12.22%, 14.85% and 7.15% as compared with the worst design, and the temperature difference can also be reduced by 63.60%, 74.86% and 57.16%. What's more, the influence level of these parameters is also compared. Before the reference value, the channel height has the greatest influence on the module bottom surface temperature, whereas after the reference value, the corner angle becomes the largest influence factor. As for the temperature difference on the module bottom surface, it is just opposite. (C) 2017 Elsevier Ltd. All rights reserved.