Abstract: An oxygen reduction device in an ion source region of inductively coupled plasma is provided. The oxygen reduction device includes a torch and an inflation sleeve. An upper end of the inflation sleeve is sealed and sleeved outside the torch, and a lower end of the inflation sleeve and the torch are arranged at an interval to form an inflation gap. An inflation hole communicating with the inflation gap is formed in an outer side wall of the inflation sleeve. An outer side face of the lower end of the inflation sleeve is protruded outwards to form an annular gas guiding protrusion. The annular gas guiding protrusion is configured for being arranged opposite to a sampling cone base arranged below the torch, and a gas outlet gap is formed between the annular gas guiding protrusion and the sampling cone base.