The invention relates to a CT/MR/near infrared optical three-mode targeted contrast agent based on the lung non-cellule cancer as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, modifying the amino terminal of a fifth-generation polyamide-amine dendrimer with DOTA-NHS; secondly, connecting folic acid to the dendrimer by polyethylene glycol; thirdly, further modifying with Cy5.5; fourthly, preparing gold nanoparticles by using the modified dendrimer as a template through sodium borohydride reduction, and chelating gadolinium ions to the dendrimer; fifthly, carrying out complete acetylization on amino remained on the surface of the dendrimer; and finally, dialyzing the reacted solution, lyophilizing to obtain a final product, and evaluating in-vivo and in-vitro CT/MR/near infrared optical three-mode contrast performance of the product. The method is simple and feasible, has excellent in-vivo and in-vitro lung non-cellule cancer cell target effect, and has a potential application prospect of targeted CT/MR/near infrared optical contrast.