Diffusion-time-dependent diffusion MRI (dMRI) has shown potentials in characterizing tumor microstructure. This study investigated the diagnostic value of time-dependent dMRI to differentiate prostate cancer pathological grades at 3T. Oscillating and pulsed gradient dMRI was performed in 55 patients, and the data were fitted with the IMPULSED model to estimate cell diameter, intracellular fraction, cellularity, and diffusivities. We found fin and cellularity increased as Gleason score increased, while diameter and Dex decreased. Cellularity achieved the highest diagnostic accuracy with an accuracy of 0.87 and area-under-the curve of 0.96, and the combination of cellularity and ADC further improved the accuracy to 0.91.