Using a microwave generator, chlorine diluted by helium was dissociated to chlorine atoms that subsequently reacted with hydrogen azide to produce the excited states of NCl(a1Δ). Meanwhile, molecular iodine with carrier gas of helium reacted with atomic chlorine to produce atomic iodine which then was pumped to excited state of I(2P1=2) by an energy transfer reaction from NCl(a1Δ). In this paper, the changes of NCl(a1Δ) and NCl(b1Σ) emission intensity is presented when I2/He is introduced into the stream of Cl/Cl2/He/HN3/NCl(a1Δ)/NCl(b1Σ). The dependences of atomic iodine I(2P1=2) on flow ratesof gases were also investigated. The optimum parameters for I(2P1=2) production are given.