A novel rare earth complex was prepared from lanthanum ( La) and vitamin C and was used as a new type of antioxidant in natural rubber /carbon black ( NR/CB) composites. Then,the effects of the vitamin C-rare earth complex on the curing characteristics of NR/CB compounds and the mechanical properties of NR/CB vulcanizates were investigated. Moreover,by means of FT-IR and according to the retention of mechanical properties and the variation of surface morphology,the effects of the rare earth complex on the antiaging properties of the NR/CB vulcanizates were also analyzed in detail and were compared with those of the commonly-used rubber antioxidants 4010NA,RD and MB. The results show that ( 1) the rare earth complex can accelerate the vulcanization of the NR/ CB compounds to a certain degree and improve the mechanical properties of the NR/CB vulcanizates; ( 2) the rare earth complex has a good antiaging effect on the NR/CB vulcanizates; ( 3) the thermo-oxidative aging resistance and UV aging resistance of the rare earth complex are close to those of 4010NA and RD and are superior to those of MB; and ( 4) the ozone aging resistance of the rare earth complex is particularly strong for the NR/CB vulcanizates,which is superior to those of RD and MB as well as to those of 4010NA with an excellent ozone aging resistance.