Abstract: An experimental device was established and it included a test pipeline with 89-mm diameter, 4.5-mm wall thickness and 300-mm length. By choosing the stoichiometric premixed C2H2-air gas as the objective, the established device was used to experimentally explore the suppression effect of the premixed gas flame propagation and explosion overpressure by the different-length aluminum silicate wool at the different positions in the pipeline. The results demonstrate that when the length of the aluminum silicate wool surpasses the critical length for the flame speed, the aluminum silicate wool can suppress the flame speed. When the length of the aluminum silicate wool surpasses the critical length for the pressure, the aluminum silicate wool can suppress the explosion overpressure. The critical length of the aluminum silicate wool for the flame speed is related to the flame speed at the inlet, whereas the critical length of the aluminum silicate wool for the explosion overpressure is relevant to the explosion overpressure at the inlet. The critical length for the pressure is smaller than that for the flame speed. It can display that the aluminum silicate wool can suppress the pressure waves more efficiently.