In this study, we have grown epitaxial wurtzite structured InAs nanosheets using Au catalysts on a GaAs{111}B substrate by molecular beam epitaxy. Through detailed electron microscopy characterization studies on grown nanosheets, it was found that these wurtzite structured InAs nanosheets grew epitaxially on the GaAs{111}B substrate, with {0001[combining macron]} catalyst/nanosheet interfaces and extensive {112[combining macron]0} surfaces. It was anticipated that the epitaxially grown InAs nanosheet can be triggered by a high supersaturation in catalysts, leading to an inclined growth leaving the substrate surface, and driven by the small lattice mismatch between the nanosheets and the substrate, with the orientation relationship of (0001[combining macron])InAs//(112[combining macron])GaAs. This study provides insights into achieving epitaxial free-standing III-V nanosheet growth.