Event-related potentials (ERP) is pertinent to medical research and clinical diagnosis. Estimation of single event-related potentials (sERP) is the objective of ERP processing. A new technique, adaptive moving averaging based method for estimation of sERP, is presented. After analysis of the properties of background noise by crossing zero, the window length of moving averaging is adaptively set according to the maximum width of the impulse noise for each recorded raw data. The experiments are made with real recorded data and the results demonstrate that the performance of sERP estimation is excellent. So the method proposed is suitable to sERP processing.