Abstract: Coal transient electromagnetic exploration is often conducted around a coal mine where man-made interference is stronger, noise in a secondary induction field signal is mostly higher, it is difficult to carry out processing and interpretation. In order to eliminate these electromagnetic interference in data, according to the morphological characteristics (One-way attenuation) of decay curve, by Kalman filtering method, suppressing interference can be quick and easy, and the original signal is better restored. By using this method to process and interpret the actual data affected by electromagnetic interference of high voltage line, comparison of data after filtering with data collected after power off of high voltage line, data have been basically consistent, demonstrating that the method is effective.