Abstract: In pressurized water reactor nuclear power plants,the primary circuit control uses theboron-lithium coordination solution.Under the existence of the boric acid in the primary circuit water,boric acid easily crystallize in the atomization system of inductively coupled plasma optical emission spectrometer,which affect the determination of the lithium ion concentration.In this study,ion exchange resin-inductively coupled plasma optical emission spectrometer online combination analysis system was developed,which used allochroic ion exchange resin to remove the boric acid of the primary circuit water.Under the optimized conditions with the detection wavelength of 610.362 nm and 670.784 nm,the recovery of standard addition and relative standard deviations are 98.4% and 101.9%,and the relative standard deviation is 0.97% and 0.42%（n=6）.The system has the advantage of simple structure,low cost,ease of building without the requirement of complexly fabricated devices,convenient operation,and completely removed boric acid.