Phase transformation in anisotropic nanocrystals is critical for enhanced surface properties of bimetallic catalysts. In this work, we report a series of phase transformed PtFe nanocomposites as catalysts for facile oxidation of glycerol to value-added tartronic acid at mild operating conditions. The lattice mismatch between Pt and Fe intrinsically drives structure reconstruction from face centered cubic (fcc) to ordered and lattice distorted face centered tetragonal (fct) phase. Surface characterization reveals that there exists an interdiffusion of Pt and Fe during phase transformation and a downward shift of binding energy for Pt species. Such transformation induces the formation of strained PtFe nanocomposites and enhanced structural coherence leading to 3-fold enhancement in catalytic activity for one-pot glycerol oxidation to tartronic acid compared with the fcc structure.