The invention discloses an initial synchronization method for multiple hot backup computers. The initial synchronization method comprises the steps that each hot backup computer receives the same externally-inputted synchronous clock signal; each hot backup computer finishes the initialization work and then transmits information A to other units, wherein the contents of the information A are that a local computer has synchronous working conditions; a certain hot backup computer receives the information A transmitted by all other hot backup computers and transmits information B to other hot backup computers, wherein the contents of the information B are that when a rising edge of next synchronous clock signal comes in, the current hot backup computer starts to work; after a certain computer receives the information B, the certain computer transmits the information B to other computers; if a certain hot backup computer does not receive the information A transmitted by other computers within continuous N (N is a preset value) synchronous clock cycles, the certain hot backup computer transmits the information B to the other computers. According to the initial synchronization method disclosed by the invention, initial synchronization of the multiple hot backup computers can be realized, and the reliability and the independent operation ability of the hot backup computer are improved.