In order to study the effect of AMT composite in removing Cl- and bronze antique's powder rust, the reactive process of AMT composite reagent with CuCl was tested. After treatment, the cottony substance was analyzed by energy dispersion spectrometer, infrared spectroscopy and X-ray diffraction, Cl- content of original reactive liquid and last lotion was analyzed by ion chromatography, the cation of original reactive liquid was analyzed by inductively coupled plasma. The results indicate that the cottony substance of AMT composite reagent reacting with CuCl is the same as the cottony substance produced by cleaning bronze with AMT composite reagent, and AMT composite reagent could penetrate inside bronze and could react sufficiently with CuCl, finally could clean out Cl-.