Hydrotherapy is a method of preventing and treating disease by applying water of different temperatures, pressures and solute contents in different forms to the body to achieve mechanical and chemical stimulation. It is the science of using water to prevent or treat disease, to correct physical or mental disorders, and to maintain and improve general health. It is now widely used in rehabilitation medicine and is accepted by a wider range of people. The main role of hydrotherapy rehabilitation treatment include: 1, clean wounds, promote healing can be used for external cleaning, cleaning burn patients wounds, surrounding skin scales and purulent secretions, etc., to promote wound healing. 2.Promote circulation and reduce pain Using warm water (37℃~39℃) or alternating hot and cold water for treatment can promote blood circulation throughout the body or limb locally, which is conducive to speeding up the healing of injured tissues. Pain relief with hot or colder (e.g., ice water) water is used to reduce pain in arthritis, rheumatism, neuritis and gout by transferring temperature stimulation to the body through heat conduction. These therapeutic effects, especially hot baths, can be enhanced by the addition of salts or chemicals (substances such as magnesium sulfate). Also can prevent the formation of venous thrombosis. 3, control inflammation and reduce edema Crushed ice is mainly used as a first aid measure to control inflammation and edema in case of burns or injuries. In severe infections crushed ice can be used to slow down blood circulation and inhibit the activity of pathogenic bacteria. In addition, for the swelling of the limb in the early stage of bone and joint injury (such as within 24h), ice is one of the routine methods of physical therapy. 4, reduce weight, facilitate walking, improve gait When the human body into the water, depending on the depth of immersion in the water, the role of buoyancy will reduce the weight load of different degrees, such as immersion to the level of the navel can reduce the weight of the lower limbs 50%, immersion to the bottom of the neck can lose 90% of the weight. Standing and walking in a reduced weight state, joint pressure decreases, pain is reduced, and the requirements for lower limb strength are reduced, so rehabilitation training is easier to carry out. Walking in water should not be too long, all should be gradual. 5, excited muscles, improve sports performance Through the use of ice on the human body for a short period of time, can strengthen the local circulation and improve muscle excitability, and therefore can obtain a higher muscle sports performance (such as endurance and explosive power). This aspect is often used to promote the movement of the paralyzed side of the limb in hemiplegic patients with good results. 6, resistance exercise, improve muscle endurance As the human body in the water movement will be affected by the viscosity of the water, and therefore resistance than in the air activity is much larger. The size of the resistance on the one hand with the movement of the size of the force surface, on the other hand, also directly related to the speed of movement, that is, the larger the force surface, the faster the speed, the greater the resistance. Based on this principle, you can use different force surface of the water sports training equipment, design different movements to target the training of damaged muscle strength. At the same time muscle endurance is also relatively improved. 7, improve coordination in the water coordination training: is to swim in the water, first in a fixed position, and then release the patient to carry out their own. Repeat the training to achieve the effect of improving coordination.