Abstract: Under the existing architecture of Web services motivated by the standard and convenient services composition,it is proposed an XML-format Web services composition description language(SCDL) based on the basic idea of object-oriented mechanism.As well,the transformation rules from SCDL to by the OO program language are given.It is first defined the domain-specified structure of services composition based on XML DTD,and then serves composition desription language is defined,followed by the transformation rules.Theoretical analysis and experimental result have shown the completeness and effectiveness of the proposed method.