This paper presents an underwater robot specifically designed for cleaning water pool, the idea comes from the requirement of Macau Water Company. We have designed underwater robots to meet the needs of cleaning job. The cleaning job can be distinguished into two main parts: bottom cleaning and side-wall cleaning. Most of the pool cleaning robots available in the market is typically a mobile robot. It is easy to find that a mobile robot cannot cleanse up some areas inside the water pool, such as the corner areas and the surface above the water level. Hence an underwater vehicle-manipulator system (UVMS) developed can tackle the cleaning issue efficiently.