The invention belongs to the technical fields of light-industry and chemical materials, and provides a Uio-66 in-situ immobilized carboxyl functionalized ionic liquid composite material as well as preparation and an application thereof. The composite material uses a metal organic skeleton material Uio-66 as a carrier and a carboxyl functionalized ionic liquid as an active component, carboxyl of the carboxyl functionalized ionic liquid and a zirconium metal cluster are subjected to coordination bonding while the Uio-66 is synthesized, the carboxyl functionalized ionic liquid is immobilized in aUio-66 pore cage in situ, and therefore the composite material is prepared. The composite material provided by the invention has the characteristics of high catalytic activity, a quick mass transferspeed, good selectivity, easy recovery and separation, environmental friendliness, and broad industrialized application prospects in addition to good physical stability and chemical stability; the composite material prepared by the method has a very good effect as a catalyst of an esterification reaction and transesterification reaction of various acids and alcohols; and the composite material hasan obvious adsorption effect on heavy metal ions contained in a liquid as an adsorbent.