Abstract: Gear tooth surface waviness is a key factor causing vibration and noise (NVH) in gear transmission processes. Currently, waviness measurement in China is primarily contact-based. To address the low efficiency of traditional contact measurement methods, this paper proposes a tooth flank waviness measurement method based on line spectral confocal technology. A measurement model for tooth flank waviness was established, enabling waviness extraction, full-tooth waviness profile splicing, and pre-processing. Furthermore, Fourier series expansion analysis was performed on the full-tooth waviness profile. Experiments involving measurements of all tooth flanks of a gear were conducted. The results demonstrate that the line spectral confocal sensor provides reliable and stable gear measurements. The Fourier analysis results fundamentally correspond to the periodic errors associated with waviness. The line spectral confocal sensor can achieve high-speed measurement of the micro-geometry of high-precision gear surfaces.