An in-depth analysis is made of the characteristics of backup power auto-switch-on， that is， it is composed of multiple steps each with its own status condition. This is because the backup auto-switch-on is in essence a sequence control process， various operation modes being greatly different from one another. A generic backup auto-switch-on scheme based on the finite state machine（FSM） and configuration is put forward， which can manage the sequence control process and condition difference. The scheme is composed of a number of input units and output units， a FSM and configuration， which can realize entirely arbitrary power auto-switch-on configuration by building I/O blocks and solve various complicated reversed auto-switch-on operation modes， while facilitating engineering maintenance and improving development efficiency.