Abstract. This paper describes a complete implementation of Ritt-Wu's characteristic sets method in the Maple system. The implemented algorithms include those with variants for computing characteristic sets of (multivariate) polynomial sets, decomposing polynomial sets into ascending sets and irreducible ascending sets, decomposing algebraic varieties into irreducible components, factorizing polynomials over algebraic number fields and solving systems of polynomial equations. Some modification and generalization of the basic algorithms and implementation strategies are discussed. The timing statistics on a set of test problems is given.