The invention discloses an online 
BIOS (basic input / output 
system) refreshing method for a multi-node 
server. The method comprises steps as follows: a two-stage gating switch circuit comprising a first-stage gating switch and second-stage gating switches is arranged between a BMC (
baseboard management controller) and CPU (
central processing unit) nodes, after initialization of the BMC is completed, a driver of an SPI (serial 
peripheral interface) controller is uploaded, an online 
BIOS refreshing command on a user side is waited, when the online 
BIOS refreshing command is received, target CPU nodes are determined, the two-stage gating switch circuit is set for gating of BIOS Flash of the target CPU nodes, a BIOS updating file is obtained from the user side, the BIOS updating file is executed for updating, and the state of the two-stage gating switch circuit is restored. With the adoption of the method, the problem about BIOS refreshing of high-density 
server nodes can be effectively solved, CPUs on a main board can be updated without 
electrification, the single BMC can manage BIOS refreshing of the multiple CPU nodes, and the method has the advantages that 
remote operation is realized, the method is simple and convenient, the hardware 
logic complexity is low, 
embedded software is simple to realize, the method is convenient to use and the user experience is good.