The disadvantages of traditional therapy for peri-implantitis have gradually shown. Er：YAG laser can be used to make up for the deficiency of traditional therapy for the functions of sterilization，disinfection，hemostasis and photobiological regulation. However，how to decontaminate the implant without damaging the surrounding tissue？How to decontaminate the implant without damaging the surface characteristics and biocompatibility of itself？These have always been a concern of researchers. In addition，more and more attention has been paid to the concrete effect of Er：YAG laser on the therapy of peri-implantitis. We will discuss the above issues in this review.