In a pyrolysis system of fixed bed, the small molecular gases from pyrolysis products of rubber seed oil were analyzed using five different feeding methods. The gas yield of rubber seed oil was calculated. The pyrolysis characteristics of rubber seed oil at high temperatures were studied. The reduction products of Fe3O4 and carbon deposition were qualitatively analyzed. The results showed that Fe3O4 promoted the cracking of rubber seed oil. After Fe3O4 was added, the amount of small molecular gases gradually increased. The reaction of solid carbon with Fe3O4 was completed during the reaction process. The maximum volume of small molecular gases produced in the mixed system was 1816.92 mL. Under injection conditions, the reduction effect of Fe3O4 was improved with increasing temperature. The conversion rate of carbon was calculated, and the lowest conversion rate of carbon deposition at 1300 degrees C was 39.99%. As revealed by the scanning electron microscopy (SEM) analysis, the carbon particles deposited in the crucible due to water cooling were obviously smaller, with a size of approximately 0.4 mu m. The carbon deposited on the wall of the tube furnace was composed of compact spheroidal carbon sheets with a metallic luster.