A self-cleaving ribozyme was comprised of a hammerhead ribozyme and its target sequence located the downstream of the hammerhead ribozyme. The self-cleaving ribozyme gene was synthesized, amplified and cloned into the Bluescript SK plasmid. The construct harboring 10 copies of the self-cleaving ribozyme gene was obtained through successively cloning for four times. The result of polyacrylamid denatured gel electrophoresis showed: the multimeric ribozymes caused self-cleaving during the transcription reaction in vitro and formed RNA step ladders from 70 nt to 706 nt, which indicates that the self-cleavage ribozyme transcripts can be used as RNA molecular mass markers.