Abstract: The construction of urban water supply projects in recent years has led to an increasing number of pressured water diversion pipe, and the treatment process of water plants requires the micro-bubbles control of water. Taking the Beikeng Reservoir in Shenzhen as an example, the distribution characteristics of micro-bubble in the pipe are studied by model tests using high-speed photographic image method. The results show that in the working condition with higher energy dissipation rate of the force stilling basin before the inlet of the pressurized pipe, the size of micro-bubbles inside the pipe is smaller and the distribution density is lower. The size of micro-bubbles in the pipe increases and the distribution density increases when the water transmission flow increases from 2.50 m~3/s to 5.35 m~3/s. The size of micro-bubbles in the pipe changes insignificantly and the distribution density decreases when the water transmission flow increases from 5.35 m~3/s to 7.64 m~3/s.The test results of micro-bubble control measures show that: the adoption of small flow rate pre-filling, the appropriate installation of exhaust valves, and reducing the diameter of the pipe can control the size and number of micro-bubbles in the pipe effectively. The research results can provide useful reference for similar projects.