The present invention relates to a process for preparing a porous hybrid comprising zeolite and chitosan and a porous hybrid prepared thereby, in particular, to a process for preparing a porous chitosan-linking compound-zeolite hybrid, which comprises the steps of: (a) forming a linking compound-zeolite intermediate by linking a linking compound to the surface of zeolite; and (b) preparing said chitosan-linking compound-zeolite hybrid by reacting said linking compound-zeolite intermediate with chitosan or a linking compound-chitosan, a porous hybrid prepared thereby, an adsorbent and a method for purifying water.