Abstract: Thermal-barrier performance of composite air-cooled vane with ceramic coatings in a highly-loaded transonic turbine has been experimentally investigated.Experimental results show that the average net thermal-barrier effectiveness on the middle section of the coated vane is 167K,but the net thermal-barrier effectivenesses at some points are measured as 145-206K.The effects of gas temperature on thermal-barrier performance of ceramic coatings are also investigated.It is found that the performance is even better at a higher temperature or higher heat flux condition.