Harmful gas collecting device applied to pouring cooling process

The invention discloses a harmful gas collecting device applied to a pouring cooling process, which comprises a collecting unit comprising a skeleton assembly, a first film cloth arranged on the skeleton assembly, and an exhaust pipe arranged on the first film cloth; and the sealing unit comprises roller shutter assemblies arranged at the two ends of the collecting unit, sealing assemblies arranged at the two ends of the collecting unit, and pressing assemblies arranged in the roller shutter assemblies. A single collecting unit can be unfolded and placed above a pouring groove, meanwhile, the two ends of the collecting unit are sealed, and therefore the single collecting unit can form a cover body with an opening in the bottom, harmful gas can be effectively collected, meanwhile, two or more collecting units can be connected end to end and combined for use, and the collecting efficiency is improved. And the cover bodies of different sizes are formed, harmful gas in the pouring grooves of different sizes can b