The invention discloses a synthesis method of 2,2'-dipyridine by using a supported bimetal nano catalyst. The method is characterized in that the supported bimetal nano catalyst M1-M2@Al2O3 is utilized to catalyze the direct coupling reaction of pyridine so as to synthesize the 2,2'-dipyridine. The supported bimetal nano catalyst M1-M2@Al2O3 uses Al2O3 as a supporter and any two different metals M1 and M2 as active components, wherein M1 and M2 are respectively and independently selected from noble metals Pd, Pt, Ru, Au, Ag and Rh, or non-noble metals Ni, Cu, Fe, Zn and Co. By using the supported bimetal nano catalyst in direct coupling production of 2,2'-dipyridine from pyridine, the method has high production efficiency, conforms to the atom economy principle in chemical industry production, does not generate any pollutant which is harmful to the environment, and thus, is a green chemical-industry intermediate production technique.