The molecular dynamics method is used to simulate a uniaxial tensile deformation of 3.8nm nano-NiAl alloy with curved amorphous-like interfaces at OK. Plastic deformation behaviour is studied by examining the strainstress relationship and the microstructural evolution characteristics. Atomic level analysis has shown that the micro-strain is essentially heterogeneous in simulated nano-phase samples. The plastic deformation is not only attributed to the plasticity of interfaces, but also accompanied with the plastic shear strain mechanism inside lattice distortion regions and grains.