The invention discloses an extrusion sludge dewatering system, wherein a sludge agitation tank, a reactor and an extrusion dewaterer are connected in turn through sludge delivery pipes; the inlet of the sludge agitation tank is connected with a sludge setting tank used for storing sludge through a first sludge pump, a second sludge pump is arranged on the sludge delivery pipe between the sludge agitation tank and the reactor; a sludge conveyor is arranged below the sludge outlet of the extrusion dewaterer, the agent outlet pipe of a first agent-adding device is connected with the sludge delivery pipe at the inlet of the sludge agitation tank; and the agent outlet pipe of a second agent-adding device is connected with the agent-adding port of the reactor. The invention has compact structure, simple operation, high degree of automation, high separating and recycling efficiency and no secondary pollution. The extrusion sludge dewatering system has better economic benefit in energy-saving, water-saving, environmental protection and other aspects. When a large amount of water is treated, the system only needs to add signal machine, thus the device has the module combination function.