Well-defined PEO-b-PMMA was prepared, initiated by macroinitiator PEO-Br, by means of ATRP, where esterification of the terminal hydroxyl group of PEO with 2-bromoisobutyryl bromide yielded a macroinitiator PEO-Br. Highly ordered microporous films (hexagonal pattern) were constructed by emulsion micelles of such amphiphilic diblock copolymer formed from a solution with CHCl3/H2O/THF=100:5:10 (v/v). We also constructed the microporous films using diblock copolymer by the current water-assisted method.