A series of conveyer rubber belts has been made by blending natural rubber (NR), styrene butadiene rubber(SBR), chloroprene rubber(GR) and additives on nylon cords, and their respective flammability has been investigated. It has been observed that: 1. By adding an antiflame agent to the belt, in addition to 70% chlorinated paraffine and antimony oxide(Sb₂O₃), the inflammability is improved remarkably to O - 2 seconds due to the synergistic effect, while a sample without antiflame B fails to pass the KS M 66713 test. 2. Physical properties, such as tensile strength, elongation at break and adhesion strength, of the sample belts have been studies by varying ratios of NR/CR from 20 to 100, and it has been observed that the higher ratios have the better physical properties.