In the IOT of intelligent agricultural greenhouse system, the data collected by the sensor nodes need to be uploaded to the remote server via the Internet, and 6LoWPAN is used between the Contiki nodes. It cannot connect directly with the traditional IPv4, so it is necessary to configure an Internet of Things gateway. By transplanting the OpenWRT system to HG255D router, the router can be changed into a small, practical embedded Linux system, so that they can run open source or developed program. This article introduces how to implement HG255D routers on the IPv6 Internet access gateway, mainly involving the compilation of the OpenWRT firmware, router configuration changes, the transplantation of gateway program, as well as the effect of demonstration.