In order to study the effects of shape and size on the molecular tailoring process of single-base propellant， three gradiently denitrated single-base propellants （seven-holes， one-hole and non-hole single-base propellants） were prepared by using hydrazine hydrate as denitration agent. Based on the Avrami model， the kinetics of the molecular tailoring process of different shapes of single‐base propellants have been investigated. The results showed that the Avrami model could be used to describe the molecular tailoring process of the three single-base propellants. The Avrami index of seven-holes single-base propellant is n>1 in the range of 70-75 ℃， indicating that the molecular tailoring reaction process was controlled by the chemical reaction process. When the temperature was in the range of 75-80 ℃， n<1， it was controlled by a combination of internal diffusion and chemical reaction. The Avrami index n<1 for one-hole and non-hole single-base propellants， and the molecular tailoring process was controlled by a combination of internal diffusion and chemical reaction. According to the Fick''s law， the diffusion coefficient D of one-hole single-base propellants was 3.8×10^-13-10.2×10^-13 m²·s^-1， and that of non-hole single-base propellants was 3.7×10^-13-5.1×10^-13 m²·s^-1. Using the Arrhenius equation， the apparent activation energies of the seven-holes， one-hole and non-hole single-base propellants were calculated to be 45.84， 52.88 and 38.26 kJ·mol^-1， respectively. The study of the kinetics of molecular tailoring reaction for different shapes of single-base propellants can provide theoretical guidance for the controllable preparation of gradiently denitrated single-base propellants.