As a digital basis of smart substation, IEC 61850 has promoted the advancements of the substation technologies. But at the same time, several design defects are also reflected in the applications. Based on in-depth analysis of the status and practical applications of IEC 61850, its advantages and defects are summed up. According to some of the requirements for smart substation development, a complementary architecture for IEC 61850 is put forward, which is no longer confined to the current standard constraints. It is pointed out that, the intelligent electronic device (IED) models of IEC 61850 and its related service models may be simplified, the Substation Configuration Description Language (SCL) needs to get rid of the weakness of low efficiency and hugeness, a new efficient communication protocol stack needs to be designed by using the Specific Communication Service Mapping (SCSM) mechanism, and the seamless communication ability with dispatching ends need to be strengthened. Finally, an improvement design as supplementary protocols for IEC 61850 standard is put forward by using the CIM/E language and the general service protocol for electric power systems.