The curing characteristics and mechanical and dynamic properties of Si69 in NR compounds by long time curing at low temperature were studied. The results indicated that the optimum curing time was lengthened and the reversion rate was decreased by adding Si69. The properties of tensile strength,modulus and tear strength were higher in optimum curing time at 140 ℃ and NR vulcanizates had better mechanical properties with Si69 2.0 phr. The mechanical properties and conservation rates were higher when long time cured in 145℃. The spin-lattice relaxation time （T2） was shortened and the crosslinking densities were increased with curing time lengthened at different curing tempera- tures. DMA results showed that Tg moved to higher temperature after adding Si69.