Finite Element (FE) models of LFET were employed to investigate Low Frequency Electromagnetic Technique (LFET) in pipeline defect detection. Two-dimensional and three-dimensional LFET simulations were carried out using the ANSYS Parametric Design Language (APDL). Magnetic Flux Leakage (MFL) signals of different defects were obtained from the established models. From the simulations and experimental results, the practicality of LFET-based pipe defect detection was demonstrated, therefore, it could be recommended for the applications in non-destructive testing of pipelines such as boiler water wall etc.