The 532 nm picosecond laser was used to etch the surface of the tantalum-silicon composite dielectric film for precision grooving. The microscopic morphology and elemental composition of the tissue after laser etching were analyzed using optical microscopy, scanning electron microscopy, laser confocal microscopy and energy spectrometry. A three-dimensional ablation model was established to analyze the temperature field of the laser interaction with the tantalum-silicon composite dielectric film. The results show that at a laser energy density of 3.24 J/cm2, the tantalum oxide dielectric film can be effectively removed without causing damage to the silica dielectric film or the substrate, thus achieving controlled-depth laser ablation processing.