A motherboard system is provided. The motherboard system includes a central processing unit (CPU), a control unit and an interface connector. The control unit is electrically connected to the CPU. The interface connector is electrically connected to the control unit and has a boot loader interface unit and a peripheral storage device interface unit, wherein the boot loader interface unit is electrically connected to the control unit and is configured for electrically connecting a system read only memory. When the power of the motherboard system is turned on, the CPU sends a read only memory fetch cycle to the control unit and fetches a booting program from the system read only memory configured in an external device via the boot loader interface unit. Accordingly, the system read only memory can be conveniently updated and maintained.