Dental health has a great impact on the overall health of an individual, however traditional dental treatment mostly uses a hand-held tooth whiling machine, which can cause inaccurate grinding and has a large thermal impact. The femtosecond laser has the characteristics of high precision and minimal thermal effect, displaying great potential in teeth cleaning. In this paper, we propose an experimental scheme that uses femtosecond laser to etch the tooth surface, further exploring its cleaning efficiency using gray level characterization of the tooth surface. The experimental results show that compared with the traditional drill, the femtosecond laser not only can remove dental plaque and pigmentation, but also causes no collateral damage to the surrounding healthy tissue, which greatly improves the accuracy and efficiency of treatment. In summary, the application of femtosecond laser in dental treatment has wide-ranging prospects, providing new ways and possibilities for achieving safer and more effective dental treatment.