Compatibility between NR and EPDM is investigated in order to improve the ozone resistance and some physical properties of NR/EPDM blends by utilisation of liquid rubbers and some homogenising agents. n-t-butylbenzothiazole-2-sulphenamide BBS is chosen as the most appropriate accelerator for sulphur vulcanisation of the blends. NR/EPDM blend ratios of 70/30 and 80/20 are chosen for comparison because the 70/30 NR/EPDM cannot resist ozone cracking longer than five days, while the 80/20 NR/EPDM fails within 24 hours under the same condition. Struktol 40MS, Rhenosin 145, liquid NR, liquid EPDM, their combinations and partial crosslinking of these two liquid rubbers at 3, 5 and 8phr are added to the 70/30 and 80/20 NR/EPDM blends. Ozone resistance and tensile properties of the blend vulcanisates are measured. The results showeed that among these additives, 3phr of fluid EPDM could best improve blend ozone resistance and tensile strength.