An information processing system includes a housing, a circuit board in the housing, a functional module in the housing, and a module fixing device in the housing. The functional module is inserted into the circuit board. The module fixing device is connected to the functional module and is connected to the circuit board. The module fixing device comprises a clamping member and an elastic member. The clamping member is movably connected to the circuit board in a first direction and a second direction opposite to the first direction, the clamping member comprises a first clamping portion to clamp the functional module. The elastic member is connected to the clamping member, the elastic member is deformable in the first direction to drive the clamping member to move in the first direction to clamp the functional module.