The heat transfer coefficient distribution of the turbine casing inner surfaces was studied experimentally by utilizing transient thermochromic liquid crystal technique.The casing investigated is composed of complex structure including impingement hole and dimples.Experiment results show that the jet impingement is a main contributing factor to heat transfer enlargement.The heat transfer coefficient near the exit hole and the impingement region is higher than others.The experiment results are helpful to the calculation of turbine casing temperature field and the control of blade tip clearance.