The invention belongs to the field of electrocatalytic moisture analysis oxygen, in particular relates to a preparation method and application of an amorphous cobalt borate nanorod efficient oxygen evolution electrocatalyst, and aims to solve the problems of high price and the like of a prior noble metal electrocatalytic oxygen evolution catalyst. Low-cost water-soluble cobalt salt and sodium tetraborate decahydrate are used as precursor reactants; a hydrothermal method is adopted to control the heating temperature and the reaction time; the obtained precipitate are centrifugally washed and freeze-dried to obtain the amorphous cobalt borate nanorod efficient oxygen evolution electrocatalyst. The preparation method has the advantages of low cost, environmental protection, simple operation and convenient post-treatment of the product, the diameter and length of the nanorod can be easily regulated and controled. Meanwhile, the amorphous cobalt borate nanorod efficient oxygen evolution electrocatalyst has the advantages of low initial over potential, low Tafel slope, high stability and the like.