Abstract: A portable magnetic flux leakage testing device for field inspection of the pipelines was developed by combining embedded configuration, signal processing a magnetic flux leakage testing. Experimental data showed that the device was of high sensitivity, high efficiency and low cost. The defects both in inside and outside walls of a pipelines could be detected by scanning only once from the outside and it had wide application prospects in the fields of metallurgy, petrochemical industry, water supply and city heating piping systems.