The invention discloses an antibody coupling nano carrier and a preparation method thereof, the antibody coupling nano carrier is prepared from the following components by weight: 100 parts of a nano carrier, 2.5-5 parts of an antibody, 6.0-25 parts of a coupling agent and 6.0-25 parts of N-hydroxy succinimide (NHS). The antibody coupling nano carrier is ideal in coupling rate, the phenomenon of precipitation produced by aggregation can be greatly reduced, the phenomenon of precipitation produced by aggregation of general nanoparticle coupling antibody is very easy to produce, nanoparticle dispersion is good, the material loss is reduced, late in-vivo and in-vitro experiments may not be affected, the preparation method is mild in conditions, and the antibody and nanoparticle damage can be avoided.