Systematic experiments were conducted to study the fretting wear behaviors of spline connections by surface modifications used for the gauge-changeable railway. Three different surface modification treatments, i.e., plasma nitriding (PN), laser quenching (LQ), and laser cladding (LC), were applied on DZ2 steel. The fretting wear volume and failure mechanism were discussed. The results show that surface modified layers can improve the fretting wear resistance compared to untreated samples. The LC layer with a lowest hardness has a lowest wear volume. While for the whole tribo-pairs, the LC/D2(QT) tribo-pair has a lowest wear volume in mixed fretting regime, but the PN/D2(QT) and LQ/D2(QT) both have a lower wear volume in slip regime. The main failure mechanism is delamination, ploughing and oxidation.