Yellow teeth caused by smoking can be restored to its normal color by scaling. Due to long-term smoking, there is a lot of smoke stains and pigmentation on the teeth, resulting in yellowing of the teeth. In this case, the yellowing of the teeth is caused by exogenous factors and can be removed by scaling. During scaling, the steps of cleaning, sandblasting and polishing can effectively remove the tobacco stains and pigments, thus restoring the original color of the teeth. However, if the yellowing of the teeth is due to endogenous factors such as tetracycline and dental fluorosis, it is not possible to restore the original color of the teeth by means of scaling, and in this case, the teeth can be whitened by means of oxidative bleaching whitening methods. Patients with yellowing teeth can go to the hospital for examination to find out whether it is due to endogenous causes or smoking, and then choose the appropriate way of improvement.