The invention provides an ion chromatography method for measuring trace chloride ions in triethyl aluminum. The method includes the steps of 1, pretreatment of a sample to be measured, wherein the TEAL sample is dissolved with isopropanol, the volume is kept at scales with secondary deionized water, ultrasonic and centrifugal treatment is carried out, and supernatant is taken, passes through a 0.22-micrometer pin type filter and an H-type pretreatment column, and then enters an ion chromatography system for analysis; 2, preparation of a work curve solution; 3, analysis of a standard addition method solution, wherein the repetitive solution is continuously injected 6 times, a chromatogram of Cl- standard addition solution analysis is obtained, the pretreated triethyl aluminum sample solution is subjected to ion chromatography analysis, the peak area of Cl- is obtained, and the content of Cl- in triethyl aluminum is obtained according to a work curve and the peak area of Cl-. The method is easy to operate, good in repeatability and high in sensitivity, the content of chlorine ions in TEAL can be effectively measured, and the problem that in the measuring process, heavy metal aluminum contaminates and damages the chromatographic column and a suppressor is solved.