Due to the advantages of safety and reliability, high accuracy and large range, laser thickness measurement is widely used in online measurement of film thickness such as paper and battery pole pieces. Scanning thickness measurement of the strip in the wide direction inevitably introduces mechanical vibration, which causes deviations in the measurement results. The lithium-ion battery pole piece was taken as an example to analyze and optimize this problem. First, the thickness of the battery pole piece and the copper foil was measured with differential thickness measurement system, then the spectrum of the battery pole piece and the copper foil was analyzed, and the similarity of the vibration laws was explored. Finally, based on the spectrum analysis, a filter was designed to process the thickness measurement data. After filtering, the range of the pole piece and copper foil are reduced by 33.4% and 73.8%, respectively, thus the thickness measurement accuracy can meet the requirements.