In this work, the structural and energetic properties of GaAs nanoparticles (NPs) are investigated using the bond order potential (BOP) based on modern classical molecular dynamics (MD) method. All MD simulations are performed by means of LAMMPS (large-scale atomic/molecular massively parallel simulator). Some physical properties such as variation of potential energy depending on temperature, order parameter, coordination number in terms of probability distribution and radial distribution function (RDF) are searched. The heat capacity () calculation is also performed as depending on temperature using a nonequilibrated molecular dynamics simulation strategy. The tendency of Ga and As atoms inside the core has been observed under temperature increase. As atoms have significant effect on the stability of GaAs NPs. Temperature dependence of these physical properties was obtained. The calculated physical properties are found to be sensitive to temperature.