A circuit board module includes a circuit board, a plurality of electronic components, a plurality of connectors and a cover. The circuit board includes a heat dissipation unit. The electronic components, the connectors and the heat dissipation unit are disposed on a first surface of the circuit board. The cover has a plurality of openings with the shapes and the sizes corresponding to the connectors and the heat dissipation unit. When the cover covers the circuit board, the openings expose the connectors and the heat dissipation unit. Users can plug and pull the connectors of the circuit board through the openings. The size of the cover is corresponding to the circuit board. The circuit board module is dust-proof and can prevent the users from accidentally touching the electronic components.