The invention discloses a battery positive pole ring online detection system. The problems that manual operation is adopted for existing positive pole ring measurement, the yield is affected, time andlabor are consumed, large manpower cost is needed, and errors occur easily are solved. The system comprises an automatic sampling mechanism used for performing sampling on positive pole rings on a conveying track, an automatic sorting mechanism and a control end, wherein the automatic sorting mechanism at least comprises a first detection station and a second detection station, and the sampled positive pole rings are picked out independently, and are conveyed to the first detection station and the second detection station; the first detection station is provided with a height detector, and the second detection station is provided with a strength detector; and the control end is used for acquiring data of the height detector and the strength detector. The battery positive pole ring onlinedetection system performs automatic random sampling on the battery positive pole rings, and equipment is not needed to be shutdown; and compared with manual sampling, more time and labor are saved. The detecting speed is increased, and the manpower cost is lowered. Detection data are automatically acquired and saved; and compared with manual recording, errors are not likely to be caused, and the manpower cost is lowered.