Poly(dimethylsiloxane) (PDMS) based soft lithography has been widely used to make microfluidic devices, while the cross-sections of the microchannels using the solid molds are mostly rectangle. We present a method for fabricating PDMS channels with a round profile, which utilizes hydrophilic/hydrophobic modification of substrates and glycerol molds. The glycerol mold was formed by letting glycerol stay on the patterned hydrophilic area surrounded by hydrophobic area. The different aspect ratios of the profiles were realized using different hydrophilic/hydrophobic modifications with small channel widths. The round profile channels with 10%-30% aspect ratios were obtained.