Objective: To study the method of extracting somatosensory evoked potential better. Methods: This article com-pares an auto-reference, auto-correlative and adaptive interference cancellation theories and techniques (AAA-ICT) used to the single trial of somatosensory evoked potential (SEP) with the traditional superposition averaging. Results: By the intensive study and analysis of the somatosensory evoked potentials from the 80 human subjects whose nervous systems are normal, We can find that the traditional superposition averaging method has its reasonable connotation on the extraction of SEP except the inevitable defects. Conclusions: Meanwhile the AAA-ICT avoids its defects. R implements another jump for the SEP extrac-tion method and has a good clinical application value.