A circuit board mounting assembly includes a chassis with a securing hole, a circuit board attached to the chassis, a drive bracket mounted in the chassis, and a latch member configured to latch the circuit board. The drive bracket comprises at least one clamp engaged with the circuit board for preventing the circuit board from moving along a first direction. The latch member comprises a retractable post movable between a latched position and an unlatched position along the first direction. When the retractable post is in the latched position, the retractable post is received through the securing hole for preventing the circuit board from moving along a second direction perpendicular to the first direction, thereby locking the circuit board to the chassis. When the retractable post is in the unlatched position, the retractable post is removed from the securing hole for unlocking the circuit board.