In this study, polydimethyl-siloxane (PDMS) film with a mushroom-shaped micropillars array was formed as both a dry adhesive patch to fix an electrode on human body and a dielectric layer of a capacitive dry electrode to sense biopotentials. The adhesion strength of the PDMS film was analyzed by numerical calculation and experimental results. The results indicated that the adhesion strength was large enough to fix the electrode on skin. Furthermore, the durability testing result demonstrated that the PDMS film had adhesion strength stability. In addition, the PDMS film was more biocompatible than the acrylic medical patch. The experimental results of biopotentials measurement presented that the qualities of electrocardiogram (ECG) and electromyogram (EMG) signals recorded by the capacitive dry electrode were comparable with those of the wet electrode (Ag/AgCl).