The invention discloses a double machine warn backup switching method achieved based on the SOA and the RS485 bus. A console system takes charge of processing switch between a host and a slave machine, the distributed storage of data, and coordinating the work of the host and the slave machine of a generating station monitoring system; the host and the slave machine judge whether or not the slave machine or the host is abnormal through messages sent by the console system and/or a heartbeat line, if the slave machine or the host is abnormal, tasks of the other side are taken over; both the host and the slave machine start all of the threads of the tasks, wherein the host mainly undertakes a data checking task, the slave machine monitors the host, receives monitoring data simultaneously, conducts filtering process on the data, and merely receives the data sent upward by smart monitoring equipment of a lower computer. The invention further discloses a double machine warm backup system achieved based on the SOA and the RS485 bus. The double machine warm backup system achieved based on the SOA and the RS485 bus comprises the console system, the host and the slave machine. The host and the slave machine can be operated simultaneously, all of task processes are in a starting state, and synchronous backup is performed on the data in a database through the console system at any time. In the process of switch, the problems of starting and loss of the data are unnecessary to consider, and therefore time is saved for double machine switch.