The physical blends of nitrocellulose(NC)/hydroxy terminated polyether(HTPE) with different proportions and NC/HTPE/toluene-2, 4-diisocyanate (TDI) cross-linked polymers were prepared by a solution mixing method. The compatibility of NC and HTPE were studied by the enthalpy of mixing method. The dynamic mechanical properties of the blends were analyzed by dynamic thermal mechanical analysis. The crosslink reaction state between NC and HTPE as well as the interaction between the molecules were studied by means of Fourier transform infrared (FT-IR) spectroscopy. Results show that two polymers are a partial miscible system and the degree of miscibility is relevant with the constitution of the blends. With the proportion of HTPE increase, the glass transition temperature of the blend system decreases gradually. When the mass fraction of NC is 30%, the T_g of NC/HTPE physical blend system is -9.8 ℃, while the T_g of the chemical crosslink system is -1.4 ℃, both the T_g of the two systems reduced greatly in contrast with the T_g of NC. Compared with the NC/HTPE physical blend system, the chemical cross-linking can make the compatibility of NC and HTPE increase. The characteristic absorption peak of isocyanate group at 2270 cm^-1 disappears after crosslink, demonstrating that the crosslink reaction is relatively complete. The stretching vibration absorption peak of hydroxy and nitro group of NC after blending shifts to low wave numbers, indicating the existence of hydrogen bond interaction between NC and HTPE. After crosslinking, the shift of hydroxy and nitro group decreases, showing that the hydrogen bond interaction between NC and HTPE is partly substituted by chemical bond interaction.