It is recommended to use multi-frame tracking measurement technology for negative electrode coating. The base material can be measured using Dacheng Precision X/β-ray surface density meter, and the single-sided pole piece and double-sided pole piece can be measured using a β-ray surface density meter. Tracking and measuring at the same point is used to subtract the influence of changes in surface density of the base material on the surface density of the pole piece, and obtain the direct quality index of the process, the net coating amount.