The shape-tunable Pt-Cu-Ni rhombic dodecahedra nanoframe is achieved via modified solvothermal and two-step etching, the first step is Pt-Cu-Ni concave rhombic dodecahedra synthetized due to oxidation etching, and the second step is Pt-Cu-Ni nanoframes obtained through the acid etching. The Pt-Cu-Ni solid rhombic dodecahedra as an intermediate product can be well controlled by adjusting the amount of reaction time and Ni precursor. Based on the formation mechanism of Pt-Cu nanoframes, the morphological evolution process of ternary nanoframe is precisely investigated according to the changes of morphology, atomic ratio and average particle size. In addition, shape-tunable Pt-Cu-Ni nanoframes catalyst shows enhanced mass activity of 0.86 A mg(-1) Pt at 0.9 V versus reversible hydrogen electrode towards oxygen reduction reaction, which is 6 times as well as that of the commercial Pt/C catalyst. Remarkably, there is a more positive onset potential of Pt-Cu-Ni nanoframes compared to other catalysts. More importantly, this synthetic method opens a promising door towards development and applications of Pt based catalysts.