Abstract: The mathematical models of two external heat transfer(EHT) codes,STAN5 and S1ICH,were compared.Both codes were employed to calculate the EHT coefficients(EHTC) of two turbine blades,i.e.:Von Karman Institute(VKI) high-pressure turbine guide vane and blade,and the results were compared with experimental data.The results show that S1ICH has higher precision on capturing onset of transition and predicting EHTC of turbine blades than STAN5.S1ICH can meet the requirement of engineering applications,thanks to its character of extensive applicability,good convergence and simple input.