Spots on the back of the hand should be considered as age spots, solar keratosis or flat warts, which can be treated with laser therapy and medication with keratolytic effect respectively. 1. Age spots: clinically known as seborrheic keratosis, occurring on the face and limbs of the exposed parts of the dark brown, rough surface of the dark brown patches, mainly seen in the elderly. Picosecond treatment can be used to remove the spots, i.e., through the photothermal effect, destroying the pigment particles and accelerating their shedding through skin metabolism, so as to achieve the effect of removing the spots. 2. Solar keratosis: insufficient sun protection, long-term sun exposure, skin aging spots. Treatment can also be used laser treatment, at the same time, pay attention to sun protection, applying isolation cream, sunscreen, etc.. 3. flat warts: brown patches raised on the skin, mostly seen on the backs of young people’s hands. The treatment can choose to have the role of keratin stripping drugs such as Vitamin A acid ointment can achieve a better therapeutic effect, or with laser treatment, such as carbon dioxide laser therapy. There are many other reasons that can lead to black spots on the back of the hand, and it is recommended that patients who are willing to be treated should go to regular hospitals for a clear diagnosis and standardized treatment under the professional guidance of specialists.