In most industrial processes, toxic pollutants and vapors are produced and released, which cause various diseases in people working in industry and irreparable damage to the environment. Industrial ventilation systems are considered as one of the most effective methods of reducing and controlling gaseous pollutants and dust particles. One of the effective systems in industrial ventilation is blowing -suction ventilation systems. In this study, the effect of flow ratio (ratio of blowing flow to suction flow) and direction of blowing jet air on the performance of blowing-suction ventilation system was investigated numerically. The mixing parameter has been used as an indicator to measure the performance of the ventilation system. The results showed that the performance of the ventilation system blowing-sucking by reducing the current ratio improved exponentially. It was also found that one of the ways to improve the performance of the blowing – suction ventilation system is to reduce the direction of the blowing angle.