Superperiodic feature was observed by scanning tunneling microscopy (STM) on the surface of highly oriented Pyrolyticgraphite (HOPG) on which silicon was sputtered. The superlattice was analyzed by the moire pattern hypothesis, and thelattice constant is 7.03 nm. For the superlattice, the observed boundaries between the superlattice and the normal graphiteareas were zigzag, which was in good agreement with the result predicted theoretically In addition, the observed latticeconstants varied slightly in the superperiodic feature area. This implies the role of intralayer strain in the formation of theobserved superlattice on the graphite surface. Superperiodic feature was observed by scanning tunneling microscopy (STM) on the surface of highly oriented Pyrolyticgraphite (HOPG) on which silicon was sputtered. The superlattice was analyzed by the moire pattern hypothesis, and thelattice constant is 7.03 nm. For the superlattice, the observed boundaries between the superlattice and the normal graphiteareas were zigzag, which was in good agreement with the result predicted theoretically In addition, the observed latticeconstants varied slightly in the superperiodic feature area. This implies the role of intralayer strain in the formation of theobserved superlattice on the graphite surface.