The invention provides a method for preparing thermo-stable irregular 1, 2-polybutadiene rubber. The method takes a compound with anti-aging function as a component of a catalyst. The catalyst used in the method is an iron catalyst system comprising an organic compound of iron element which is a transition metal, an organic aluminum compound, dialkyl phosphate compounds and 2, 6-dialkyl-4-(dialkyl aminomethyl) phenol; the preparation method can avoid heat crosslinking of the 1, 2-polybutadiene rubber in the processes of polymerization and production, and cause an age inhibitor to be dispersedevenly in the 1, 2-polybutadiene rubber. The irregular 1, 2-polybutadiene rubber gel-free prepared by the method has outstanding thermal stability, and the prepared thermo-stable irregular 1, 2-polybutadiene rubber has content of 1, 2-structure over 70 percent.