The competition between attraction and diffusion determines the kinetics of non-equilibrium aggregation process.The formation of silver nanoclusters through non-equilibrium aggregation of silver atoms in solution was simulated by molecular dynamics as a model system to study the influence of the competition between attraction and diffusion on the aggregation process by varying concentration and temperature.It has been found that the aggregation time decreases monotonically with increasing concentration of silver atoms because of increasing attraction,while initially decreasing and then increasing with increasing temperature because of the competition between accelerated attractive motion and increasing diffusive motion of silver atoms.A mean field approximation was employed to develop a phenomenological model describing the mechanism of temperature dependence of aggregation time. The competition between attraction and diffusion determines the kinetics of non-equilibrium aggregation process. The formation of silver nanoclusters through non-equilibrium aggregation of silver atoms in solution was simulated by molecular dynamics as a model system to study the influence of the competition between attraction and diffusion on the aggregation process by varying concentration and temperature. It has been found that the aggregation time decreases monotonically with increasing concentration of silver atoms because of increasing attraction, while initially decreasing and then increasing with increasing temperature because of the competition between accelerated attractive motion and increasing diffusive motion of silver atoms. A mean field approximation was employed to develop a phenomenological model describing the mechanism of temperature dependence of aggregation time.