Disclosed is a method for preparing a matrix containing metal-organic frameworks (MOFs), comprising the steps of: 1) mixing an organic ligand precursor solution and an anionic polymer-containing solution to produce a mixed solution; and 2) adding a metal salt to the mixture solution. In addition, the present disclosure provides a matrix containing MOFs prepared according to the preparation method, and an adsorbent comprising the same. Furthermore, a method for performing fluid separation by using a matrix containing MOFs prepared according to the preparation method is disclosed.