Abstract: For the magnetic leakage flux system for steel tube flaw online inspection,normally multi-sensor technique is used to ensure the detecting speed and sensibility.As one of the critical steps of the detecting system,signal transmission is directly related to the inspection result.The said multi-sensor transmission mode is described,and all the steps for signal transmission of the said magnetic leakage flux system are studied,having developed the proper transmission mode for each individual transmission step.Relevant operation practice shows that the transmission modes as developed for all the steps are very effective.