The invention provides a method and application for realizing one-step purification and immobilization of a foreign protein through a magnetic induction protein serving as a purification label, and a universal vector. The method comprises the following steps: (1) by taking pET-28a(+) as a vector plasmid, inserting a magnetic induction protein gene into the vector plasmid, thus building the universal vector; (2) inserting a foreign protein gene into the universal vector, thus building a recombinant expression plasmid, and introducing the recombinant expression plasmid into a host cell, thus obtaining a recombinant strain; (3) cultivating the recombinant strain, inducing foreign protein expression, collecting a product, and feeding nano iron beads into the product, thus realizing one-step purification and immobilization of the foreign protein. Sites from 5' to 3' of the universal vector comprise the following elements in sequence: a promoter T7, the magnetic induction protein gene, a thrombin cleavage site, a linker, a multiple-cloning site and a terminator T7. The invention provides the method and the application for realizing one-step foreign protein purification and immobilization, which are easy to operate and have the advantages of improving the efficiency and reducing the cost.