The helical mechanoclinic deformation of a main-chain chiral smectic elastomer, which is prepared by a crosslinking reaction under twist deformation, is investigated. The twist deformation induces a layer tilt angle that depends on the handedness of twist. The layer tilt angle in the right-handedly twisted elastomer, of which the handedness is consistent with that of the helix in the SmC* phase of the non-crosslinked backbone polymer, is estimated to be up to 16 degrees at room temperature, although that in the left-handedly twisted elastomer is less than several degrees. The experiments provide evidence of chiral coupling between tilt and twist for helical mechanoclinic deformation in the chiral smectic system.