Through inventory modeling and calculating, three kinds of chemical analytical method for the determination of total iron content in iron ores (acid dissolution method, alkali fusion method and microwave digestion method) were assessed and compared in the respects of human health, ecosystem quality, climate change and resource consumption by means of life cycle assessment (LCA) software SimaPro7 and assessment mode IMPACT 2002 + (IMPact Assessment of Chemical Toxics). With the assessment of three methods, it is found that human health, climate change and resource consumption are the main impacts on the environment. The single score assessment of life cycle of the above chemical analysis procedures were calculated and the results are 1.97, 1.81, 0.07 mPt for the alkali fusion method, acid dissolution method and microwave digestion method, respectively. The environmental impacts of alkali fusion method and acid dissolution method are respectively 28 times and 26 times of that of microwave digestion method. For human health hazard, the single score assessments of the alkali fusion method, acid dissolution method and microwave digestion method are 1.15, 1.07, 0.039 6 mPt, respectively. The carbon footprints for the alkali fusion method, acid dissolution method and microwave digestion are 5.12, 4.62, 0.189 kg CO_2 eq, respectively. It suggests that the emissions of microwave digestion method are the minimum and it could be called the most environmental friendly method. Compared to the alkali fusion method and the acid dissolution method, microwave digestion method obviously has more advantages, and is worth to be recommended as the best chemical analytical method.