The fourth harmonic of the YAG fundamental 1.064m m is used to generate the electronically excited iodine I(52p1/2) through the photolysis of CF3I.The direct detection of the decay of the fluorescence at 1.315 m m has been made to investigate the spontaneous radiation life time of I(52p1/2) and the quenching rate constants of the electronically excited iodine atom by CF3I、O2 and He. The results are: 0.0370.005s，0.605torr-1s-1,2.25torr-1s-1 and 0.22torr-1s-1 respectively。