The invention discloses an oleanolic acid molecularly imprinted polymer and a preparation method and application thereof. The preparation method comprises the following steps that 1, a computer simulates an oleanolic acid molecularly imprinted polymer preassembling system; 2, functional polymerization microspheres are prepared; 3, the oleanolic acid surface molecularly imprinted polymer is prepared; 4, the surface imprinted polymer template molecule is eluted. The preparation efficiency and adsorption performance of the molecularly imprinted polymer are improved; recognition sites of the oleanolic acid molecularly imprinted polymer obtained through two-step precipitation polymerization are located on the surface of the polymer, and the oleanolic acid molecularly imprinted polymer has the advantages of being regular in shape, controllable in particle size, high in bonding speed, good in adsorption performance and the like; the obtained polymer can be used as solid phase filler and used for oleanolic acid separation and purification and has the wide application prospect.