Abstract: A portable magnetic flux leakage testing device for field inspection of the pipelines has been developed by combining embedded technology,signal processing and magnetic flux leakage testing.As a result of the embedded module,the circuit design has been simplified and the system's overall performance has been improved.Experimental data show that the device is of high sensitivity,high efficiency and low cost.The defects which are depth of 0.2mm in outside walls of a pipelines can be detected out by scanning only once form the outside and it has wide application prospects in the fields of metallurgy,petrochemical industry,water supply and city warming facilities.