Whether the hydrocarbon reaction is sufficient during the preparation of carbon black is a key issue in the production design stage. In this paper, acetylene and benzene are used as raw materials, and oxygen is used as oxidant to prepare carbon black and hydrogen by oxidative cracking. The addition of oxygen is to burn some raw materials to provide heat for the reactor. The simulation was carried out under the energy balance inlet flow rate of acetylene / benzene / oxygen at 8:30:8(m/s). It was found that there were still some benzene and oxygen in the reaction furnace, so the simulation under the energy balance conditions of8:28:6.2(m/s), 8:26:4.5(m/s) and 8:24:2.8(m/s) was added. The results show that the conversion rates of carbon black and hydrogen under these four conditions are higher than 50%. Under the condition of 8:30:8(m/s), the conversion rate of carbon black and hydrogen is slightly lower than that of the other three conditions. In addition, it was found that under the condition of 8:24:2.8(m/s), the average temperature of the cracking section was higher, the yield of carbon black and hydrogen was higher, and the cracking effect was better. This shows that under the energy balance intake condition, appropriately reducing the intake flow rate of benzene and oxygen will make the reaction more sufficient and more conducive to improving the reaction efficiency.