The invention discloses a server supporting cascade connection of multiple backboards. The server comprises a mainboard, the mainboard is provided with a BMC, a mainboard low-speed connector, an Expander chip and a plurality of mainboard high-speed connectors, the BMC is connected to the mainboard low-speed connector through an I2C bus, and the BMC is connected to the Expander chip through the I2C bus; a plurality of backboards, each backboard is provided with an I2C repeater, a backboard low-speed connector and a backboard high-speed connector, the backboard low-speed connector and the backboard high-speed connector are connected with the I2C repeater, the multiple backboard low-speed connectors are sequentially connected in series and then connected with the mainboard low-speed connectors, and each backboard corresponds to one mainboard high-speed connector, each backboard high-speed connector is connected with the corresponding mainboard high-speed connector and then is connected to the Expander chip; the BMC is configured to detect the in-place backboards and enable the I2C repeater of any in-place backboard, and the backboards where the enabled I2C repeaters are located serve as gated backboards. The server provided by the invention solves the problem of duplicate I2C addresses of cascaded backboards, improves the polling efficiency of the BMC accessing the backboard equipment, and reduces the load of the I2C bus.