A highly selective morphology formation of Cu-Ni bimetallic nanocrystals is developed with a solvothermal method, using poly(vinylpyrrolidone) (PVP) as capping agent and aniline as reducing agent in benzyl alcohol. It is shown that temperature is crucial to the controlled synthesis of nanocrystals, and that Cu-Ni nanoparticles evolve from hexagonal nanoplates to nanowires with increasing the concentration of pyrrolidone unit. The synthetic Cu-Ni hexagonal nanoplates and nanowires are well dispersed and have high crystallinity, purity, uniformity of shape and size, and face-centered cubic lattice structure. Furthermore, a mechanism of the formation of Cu-Ni nanocrystals is proposed, and the functions of capping agent, reducing agent, solvent, etc. are discussed. It is also found that both nanoplates and nanowires show better catalytic activities in o-xylene combustion than the conventional catalyst. Especially, the Cu-Ni nanowire catalyst exhibits the most excellent catalytic performance due to the formation of durian-like surface structure. (C) 2017 Elsevier B.V. All rights reserved.