The invention relates to an extruder protection device and protection method for a plastic film recovery system. The extruder protection device comprises a main extruder protection device body, a feeding machine protection device body and an intelligent protection device body; the main extruder protection device body comprises a frequency changer V1, a breaker QF1, a breaker QF2, a breaker QF3 and an intelligent ampere meter PA1; the wire feeding ends of the breaker QF1, the breaker QF2 and the breaker QF3 are connected with three-phase wires A, B, C of a power grid, the wire discharging ends of the breaker QF1, the breaker QF2 and the breaker QF3 are connected with a wire feeding end of the frequency changer V1 through an electric reactor L1, an electric reactor L2 and an electric reactor L3 correspondingly, and the wire discharging end of the frequency changer V1 is connected with a main extruder; and the wire feeding end of the intelligent ampere meter PA1 is connected with the A-phase wire of the power grid through a breaker QF4, the wire discharging end of the intelligent ampere meter PA1 is connected with the null line N of the power grid, the circuit between the breaker QF3 and the electric reactor L3 is connected with a current transformer T1 in series, and two wiring ends of the current transformer T1 are connected with a coil of the intelligent ampere meter PA1 correspondingly. By means of the extruder protection device and protection method, the fault rate of the extruder is lowered, and the maintenance cost is saved.