The structural properties and transport properties of electrolyte solutions are investigated by smart Brownian dynamics simulation based on the primitive model. To test the simulation program, the radial distribution functions of ions g+−(r) and g++(r) for KCl solution are calculated and compared with the results of previous simulations. And then, the effects of ions diameter and concentration on the structural properties and transport properties of electrolyte solution at 298K are extensively simulated. The results indicate that both the radial distribution function and the self-diffusion coefficient are more sensitive to the ion size than salt concentration. As the radius ratio of cation to anion increases, self-diffusion coefficients of both cation and anion become larger.