One kind of combustible gas alarms based on industrial Ethernet was designed to prevent the gas leakage in industrial production sites. The alarm adopted the high performance microprocessor LPC2214 as the main chip. The embedded operating system μC/OS-Ⅱ and TCP/IP protocol stack ulP running on LPC2214 con-stitute a development platform of application of the combustible gas alarm. The test shows that it can automati-cally and continuously detect combustible gas in industrial production sites in several positions;it can give out sound-light alarm and take protective measures immediately against the gas leakage ; and it can send the detected data to PC through the Etheruet interface to realize the remote detection. The designed project provides a refer-ence to design industrial devices based on industrial Ethernet.