Hair not only has a physiological role in protecting the scalp, but also has a decorative role in expressing a person’s gender, age and personality. Having a beautiful hair can increase your beauty and confidence. Scalp hair loss can cause serious physical and psychological damage to patients. There are two common types of scalp hair loss: one is scarring hair loss and the other is seborrheic baldness. The two types of baldness behave differently. Scarring baldness is characterized by concentrated hair loss with normal surrounding hair, while seborrheic baldness is characterized by thinning hair, often on the forehead and top of the head. Due to the different manifestations of hair deficiency, the treatment methods are also different, there are two main types: expander method and hair transplantation method. The expander method is to bury a water capsule (expander) under the normal scalp and keep pumping water to make the normal scalp grow, and after removing the scar, the enlarged scalp will cover the trauma to make hair grow in the area without hair. The hair transplantation method is to cut a strip of scalp from the occipital area, divide it into individual follicular units and plant them in the sparse hair areas to achieve the effect of encryption. Both methods redistribute the hair without increasing the number of hairs, and work well for patients with a hair deficiency of no more than 1/4, and less well for patients with few remaining hairs. We hope that tissue engineering can be applied to the clinic as soon as possible to bring light to patients with severe baldness.