The effects of curing parameter (R)，ratio of plasticizer to binder (P_l/P_o) and crosslinker (CA) content on the crosslink network and mechanical properties of the NEPE propellant with low smoke were studied by the swelling experiment，uniaxial tensile and dynamic mechanical test (DMA). Results show that the crosslink density (ν_e)，initial modulus (E_o) and maximum tensile strength (σ_m) of the propellant reach to the maximum，as the curing parameter (R) approaching to 1.5; the parameters (ν_e，E_o and σ_m) mentioned above increase with the decreasing of P_l/P_o from 2.8 to 2.0 and with increasing of CA in the range of 0.00%-0.10%，the maximum elongation (ε_m) and elongation at break (ε_b) of the propellant increase as P_l/P_o increases (or R and CA decreases); the loss factors (tanδ_α and tanδ_β) of the propellant increase with the increasing of P_l/P_o and CA，while the glass and secondary transitional temperatures (T_g and T_β) of the propellant，which are approximately -33 ℃ and -56 ℃，are slightly affected by R，P_l/P_o and CA.