The utility model provides an online detecting sorting system for surface defects of a lithium battery pole piece. The online detecting sorting system is characterized in that synchronous real-time online detection of the front surface and the back surface of the pole piece is realized by a pole pipe conveying device, a pole piece recognizing and detecting part, a pole piece master control unit, a pole piece sorting device and a human-computer interface part. The online detecting sorting system has the advantages that the mechanical structure is simple, the front surface and the back surface of the pole piece can be synchronously detected through a simple detection channel, the operation is simple and practical, the cost is low, the detection speed is high and generally more than two pieces per second, and the detection precision is also high; the embedded visual recognition detection technology adopted in the system realizes zero omission ratio and less than 2% of false drop rate, and thus high precision is ensured; in addition, secondary damage to the pole piece is avoided; the practicability is high, and long-time operation in an industrial site is realized due to the long running time of the system; the maintenance is convenient; the transferability is high.