Abstract: To investigate the effect of CO₂ on dust-laden gas deflagration flame propagation under obstacle conditions, a systematic experimental study was conducted using a self-developed meso-scale explosion platform. The flame propagation process and the variation law in flame speed within the pipeline were examined under different CO₂ volume fractions and obstacle configurations. The results show that at low CO₂ volume fractions, flame propagation accelerates due to airflow disturbances and uneven CO₂ diffusion in the pipeline. As the CO₂ volume fraction increases, the flame propagation speed decreases. At a CO₂ volume fraction of 6%, a distinct cellular structure appears on the flame, indicating that the inhibition effect reaches its optimum. When obstacles are introduced, at CO₂ volume fractions of 2% and 4%, the flame speed variation in the front section of the pipeline is similar to that under unobstructed conditions, while significant changes occur in the middle and rear sections. In this case, obstacles become the dominant factor affecting flame propagation, exhibiting a certain coupling effect with CO₂. The inhibition effect of CO₂ on flame propagation speed is enhanced, resulting in a marked decrease in flame speed. At a CO₂ volume fraction of 6%, the addition of obstacles has a minor effect on flame speed, and CO₂ volume fraction becomes the dominant factor influencing flame propagation.