In order to study the flow and heat transfer characteristics of microchannels with staggered internal ribs,the influence of the rib shape on the thermal performance of the microchannel was analyzed numerically. The thermal performance of the microchannels with four different shape ribs which are rectangular ribs, rhombus ribs, triangular ribs and circular ribs was compared with that of smooth rectangular microchannel. The results show that the Nusselt numbers of microchannels with rectangular ribs, rhombus ribs, triangular ribs and circular ribs are greatly larger than that of smooth rectangular microchannel. And the maximum Nusselt numbers of microchannels with four different shape ribs are 2.59, 2.71, 2.90 and 2.48 times of the smooth rectangular microchannel, respectively. Therefore, the ribs have a significant strengthening effect on the heat transfer characteristics of the microchannel. The vortices generated behind the staggered internal ribs are caused by the fluid, which realizes the overall enhanced heat transfer of the entire flow field and greatly improves the heat transfer characteristics of the microchannels. In addition, the application of staggered internal ribs also increases the frictional factor of the microchannels. The maximum frictional factors of rectangular ribs, rhombus ribs, triangular ribs and circular ribs are 8.66, 7.96, 17.50 and 5.96 times of smooth rectangular microchannel, respectively.