Disclosed are an SOPC-based NAT implementation method and device. The steps comprise: a learning/processing module judging whether it can process the information itself; if so, the learning/processing module performs processing according to contents learned previously, and then submits a processing result to an NAT processing module, otherwise, received information is submitted to a processor for processing. The device comprises a processor module, a learning/processing module, an Ethernet interface module, an extracting module, a data buffer module, an NAT processing module, and an NAT reverse processing module. The present invention implements NAT processing based on an SOPC, makes full use of the advantages of a processor and logic processing to rationally assign respective implementation functions of the processor and the logic processing, and uses a learning/processing module to make up for shortcomings of processing capability of a processor module. Moreover, the present invention also has the advantages of flexible NAT processing, fast processing, low costs and low power consumption, and has good economic and social benefits. The present invention can be widely applied to various NAT processing systems.