The effective storage time (i.e. storage life) of constant viscosity natural rubbers prepared with hydroxylamine hydrochloride, hydroxylammonium sulphate, hydrazine hydrate, aniline and semicarbazide hydrochloride respectively were investigated with heat accelerated storage aging combined with differential scanning calorimeter(DSC) method as well as the heat aging life equation. The results show that the effective storage time of constant viscosity natural rubber prepared with hydroxylamine hydrochloride is 19.2 years at 30°C, 39.4 years at 25°C and 82.9 years at 20°C. The effective storage time of constant viscosity natural rubber prepared with hydroxylammonium sulphate is 16.3 years at 30°C, 32.6 years at 25°C and 66.5 years at 20°C. The effective storage time of constant viscosity natural rubber prepared with hydrazine hydrate is 42.5 years at 30°C, 85.9 years at 25°C and 177.9 years at 20°C. The effective storage time of constant viscosity natural rubber prepared with aniline is 30.4 years at 30°C, 66.7 years at 25°C and 150.2 years at 20°C. The effective storage time of constant viscosity natural rubber prepared with semicarbazide hydrochloride is 13.5 years at 30°C, 27.4 years at 25°C and 57.1 years at 20°C.