1. Due to usual control methods making defects to retainable load system, fuzzy control with PWM is adopted, which has reached good control results.

2. Fuzzy control with PWM used in the retainable load equipment is presented in this paper.

3. China is a typical country that is in serious lack of water. China's national economy of retainable development has been interfered by it.

4. The interchange of the optical fiber guide light needle and the needle core of a retainable needle are not needed when in use, and the blood efflux because of inexperienced operation can be avoided.

5. It is time to move beyond the disposable, throw-away product era, and usher in a new generation of the sustainable, retainable and reusable.