Patients often suffer from sensitivity and pain while preparing the seats of occlusal rests of clasps on abutment teeth with hypersensitive dentine for removable partial dentures prosthesis. Base Nd-YAG laser desensitization effect by making a hard surface layer in the hypersensitive dentine of the abutment teeth, We use this method to treat the teeth before and after occlusal seats of clasps preparation, 20 patients, more than 30 occlusal seats of clasp rests are completed smoothly without any suffering since 1991. All the patients wear their dentures satisfactorily without afterward side effect. After half one year to four years followed observation all the rests adapt to their seats well without marking wear, We believe that the desensitizing effect of Nd-YAG Laser is effective in preparing occlusal seats for removable partial denture prosthesis.