The desorption of surfactant and sintering of surface modified Pd xNi1-x nanoparticles are studied. The surface energy of the nanoparticles depends on the composition and is related to the desorption temperature of surfactant from the nanoparticle surface. For the alloys with higher Ni content, the surface energy is higher and the desorption temperature of surfactant is also higher. With the same composition, the desorption temperature of stearic acid (SA) is always higher than that of polyethylene glycol (PEG) because SA has a higher thermal resistance. After surface modification, the surface energy of the nanoparticles is changed. During heating, the more stable nanoparticles have less sintering and grain growth. Surface modification not only changes the surface energy of the nanoparticles but also prevents the nanoparticles from sintering. SA has better thermal resistance than PEG and shows better suppressing of sintering of the nanoparticles.