The soft lithographic fabrication of free-standing ceramic microparts faces two great challenges: filling concentrated suspensions into microcavities of poly(dimethylsiloxane) (PDMS) molds completely and demolding green microparts from PDMS molds without any accompanying defects. In this paper, poly (3-sulfopropyl methacrylate potassium salt) (PSPMK) brushes are grafted onto the surfaces of PDMS molds by surface-initiated atom transfer radical polymerization to obtain moisture-sensitive PDMS molds. Application of the PDMS@PSPMK molds for fabricating free-standing, defect-free ceramic microparts is demonstrated by producing alumina microchannel parts with a lateral feature size of 80 µm from a concentrated aqueous suspension using microtransfer molding. During the molding process, the hydrophilic PSPMK brushes enable the suspension to fill the microcavities of the PDMS@PSPMK molds completely. During the subsequent drying process, the PSPMK brushes gradually dehydrate and collapse while the suspension loses moisture, which makes demolding easier after complete drying. The moisture-sensitive PDMS@PSPMK molds can be reused more than 10 times for the high-precision fabrication of free-standing ceramic microparts.