本文简要介绍了NAT 技术的原理及应用，说明由于NAT 的特性造成主机无法主动与处于NAT 后方的主机通讯的问题，并就这个问题探讨主机穿越NAT 与其后的主机进行通讯的技术，以及该技术的实际应用方案。关键词：NAT 穿越；UDP；网络通讯Abstract:This text introduces theory and application of NAT’s technology,and it explains that the communication between computers and NAT rear computers have problem for NAT characteristic,and it dicusses the technology that computers communicte with NAT rear computers through NAT and the project in practice application of this technology.Key words:through NAT;UDP;communication of network