The invention provides a paramagnetic metal complex and a synthetic method and application thereof. The paramagnetic metal complex is an arabinogalactan-modified 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacethyl paramagnetic metal complex. A magnetic resonance imaging contrast agent prepared from the paramagnetic metal complex has high stability, water solubility and relaxation rate and is targeted to liver and kidney, so that targeted imaging is realized, and the imaging contrast and definition are improved. The paramagnetic metal complex has a good effect on raising the early diagnosis levels of diseases of liver and kidney organs, is about 2 times the relaxation rate of dotarem, has very long targeted radiography imaging time, can be easily prepared into a solution with required concentration for intravenous injection, is suitable for sterilizing and disinfecting with a hot pressing method, can be selectively identified by an asialoglycoprotein receptor on a liver parenchyma surface, and has high selectivity on livers of human beings or other mammals.