Abstract: Detailed heat transfer measurements were conducted on the turbine blade surface of a large scale low speed turbine cascade with injection on the surface of turbine blade.Local film cooling effectiveness and heat transfer coefficient with coolant injection were determined at different blowing ratios.In conjunction with the previous measurements of the flow field,the behaviours of turbine blade surface film cooling and heat transfer were studied.The results show that turbine blade surface film cooling and heat transfer are different greatly in different hole array position.The coverage of the coolant on the surface is mainly determined by blowing ratio for same geometry.It was also observed that coolant injection made the overall averaged heat transfer increase remarkably with blowing ratio and then made the thermal loads on the surface decrease effectively.