We present an interface synthesis tool (design compiler) which can generate interface circuits automatically to expedite the IP (silicon intellectual property) integration process in SoC designs. The protocol specification issue is first addressed and a programming paradigm in SystemC language is developed. The methodology for interface synthesis is next elaborated. Conventional compiler techniques such as lexical analysis, syntax parsing and code generation are applied plus the new processing specific to interface synthesis. This includes protocol signal mapping proxy for additional semantic information, interface FSM synthesis for the controller of protocol conversion and architecture template mapping for the underlined hardware. Various interface design examples are conducted and the experimental results show the competitiveness of the proposed synthesis tool.