This study aims to systematically analyze the key parameters of the reflow process that influence the uniformity of the chromium passivation film coated on tinplate. The distribution characteristics of the chromium passivation film coated on the tinplate surface under different treatment conditions w ere systematically characterized using the scanning Kelvin probe technique,X-ray photoelectron spectroscopy,and X-ray diffraction. Results indicate that the use of flux reduces the porosity of tin coating,thereby favoring the uniform grow th of the passivation film. Furthermore,an increase in the reflow pow er and quenching temperature facilitates the homogeneous distribution of the passivation film on the tinplate surface,particularly w hen treated w ith electrolytic cathodic sodium dichromate. This study aims to systematically analyze the key parameters of the reflow process that influence the uniformity of the chromium passivation film coated on tinplate. The distribution characteristics of the chromium passivation film coated on the tinplate surface under different treatment conditions w ere systematically characterized by the scanning Kelvin probe technique, X-ray photoelectron spectroscopy, and X-ray diffraction. Results that indicate the use of flux reduces the porosity of and quenching temperature facilitates the homogeneous distribution of the passivation film on the tinplate surface, particularly w hen treated w ith electrolytic cathodic sodium dichromate.