The diffusion coefficients of aqueous L-threonine solutions were determined from 298.15 K to 328.15 K by the metallic diaphragm cell method with accuracy, promptness and convenience. Meanwhile, the densities and viscosities of the solutions were also determined and correlated. Based on a semi-empirical model for correlating the diffusion coefficients of some amino acids in their aqueous solutions, a new semi-empirical model for correlating the diffusion coefficients involving temperature was provided, which is more comprehensive and less experiment dependent compared to the previous model. The fitting results are satisfactory. Compared to a former model for correlating the diffusion coefficients of solid organic salts in their aqueous solutions, this model provides significant improvement in correlation of diffusion coefficients with different temperatures avoiding arduous work.