The invention relates to an on-line atmospheric corrosion measuring device which mainly solves the problems that in the prior art, the measurement accuracy is low and operation is complex. The on-line atmospheric corrosion measuring device comprises epoxy resin daub, at least one electrode set and lead wires; each electrode set is composed of a work electrode with the lead wire, a counter electrode and a reference electrode, and all the electrode sets are entirely packed in the epoxy resin daub; the section of each counter electrode is in the shape of a circular ring, the work electrodes penetrate through the center of the circular rings and are insulated, and the section of each work electrode is in the shape of a circle, wherein a hole is formed in the center of the circle; the reference electrodes penetrate through the holes and are insulated. According to the technical scheme, the problems are well solved, and the device can be applied in on-line atmospheric corrosion measuring.