As large amount of SDH optical systems are deployed in metropolitan area network (MAN) and access network, the scale and complexity of SDH management network is increasing dramatically. It is a very challenging task to design a robust and effective element management system (EMS) for large-scale SDH network. As well known, OSI's network architecture has been adopted in traditional SDH network management system for a long time. But it has been proved that OSI stack has many limits, such as complexity of implementation, high resource consumption and low efficiency. This paper presents a method different from that of OSI to build SDH management network. The presented method is based on lightweight IP stack and layered routing scheme of OSPF. By this method, the number of network elements of the managed SDH network can be increased remarkably without loss of management performance. Analysis of other merits of this method is also given. The implementation of EMS based on this method is introduced.