Metal detector is used more and more widely in the modern social life, it acquires much attention because of its powerful detection capabilities. This article introduces the design and implementation of an intelligent metal detector which is based on TMS320LF-2407.Adopt giant magneto resistive (GMR) sensor with the type of AA006-02. Describe the hardware component, software design, working principle and main functions of the system in detail. The core of the whole contains the probe design and control circuits. The probe: oscillator circuit is constituted by the 555 timer, it provide the sine wave signal for the coil. The control circuits: the signal which is collect by the GMR sensor is processed by voltage amplifier and filtering circuit, the peak detection circuit and A / D conversion, The signal can accurately reflect the characteristic parameters of the received signal, stability, and can eliminate interference.Practice shows that this metal detector with the method can greatly reduce the malfunction rate on the base of meeting the sensitivity.