Abstract: The increase of inlet gas temperature will lead to security problem of turbine blades.To ensure the safe operation of gas turbines, the composite structure is an effective way to enhance the cooling performance of the channels to solve the problem.The SST k-ω turbulence model is chosen to numerically simulate the flow and heat transfer characteristics of the two-pass channel.The thermal performance of the circular rib composite structure, the fan-shaped rib composite structure, and the calabash rib composite structure are compared with the solely V-shaped rib at Re of 10 000 to 60 000,aiming to explore the rib structure with the best heat transfer effect from the three composite structures of the turbine blade.The investigation concludes that the thermal performance of the composite structures augmentable compared the pure V-shaped rib.The best thermal performance is the composite structure of the calabash rib.The Nu of the calabash composite rib increases by 4.33～6.6% compared to the solely V-shaped rib, the calabash rib composite structure f is larger by 0.04～4.48% compared to the solely V-shaped rib, and the calabash composite structure f reduces by 3.67～5.21% compared to the fan rib composite structure.It concludes that the thermal performance index（η） of the composite structure is enhanced compared to the channel with solely V-shaped rib.The composite structure of calabash rib has the best thermal performance index, and the maximum value of η reaches 2.13.The η of the calabash rib composite structure is increased by 25.51～32.98% and 4.73～10.51% compared to 45° oblique square ribs and 45° oblique petal-shaped ribs, respectively.And the composite structure with low ribs and V-ribs has a significantly higher thermal performance than the composite structure with dimples and V-ribs.The proposed composite structure of calabash rib has great potential to enhance the thermal hydraulic performance of the cooling channel for gas turbine blade.