This study aims at numerical investigations on aerodynamic performance improvement of highly loaded low pressure turbine (LPT) airfoils by use of trailing edge device whose design concept is taken from Gurney flap for a racing car rear wing. The newly proposed device in this study, called localized Gurney flap (LGF), is a small protrusion on the pressure surface near the trailing edge. The purpose of the device is to reduce the secondary flow effects near the hub section of the LPT cascade with no severe additional aerodynamic penalties. Based on the original shape of LGF, DoE (Design of Experiment) is carried out to explore different types of devices that exhibit better performance than the original device numerically.