A dynamic (t, n)-threshold secret sharing scheme based on factorization is proposed in this paper. It has following properties: (1) the dealer can renew the secret key of the system without renewing the shadows of the participants; (2) when some participants’ shadows are revealed, they can be renewed without any effect on the others; (3) a new shadow can be generated for a new participant without any effect on others; (4) the shadows can be reused for many times; (5) the secret key of the system can be recovered in a parallel process.