Abstract : China is one of the countries with scarce water resources. The lack of fresh water will affect people's normal life and social and economic development, which puts the construction of comprehensive automation of urban water supply system, one of the important facilities for social and economic development, on the agenda. To this end, this paper introduces the characteristics and technological evolution of soft starter, frequency converter, and brushless and ringless starter, as well as their application in urban water supply system. Keywords : municipal engineering; control equipment; application; soft starter; frequency converter; brushless and ringless starter 1 Introduction Urban water supply system is one of the most important facilities in people's lives. Ensuring safe and stable water supply is a key link in people's lives and urban economic construction. In addition, water conservation, reducing power consumption and reducing water production costs are the goals of water supply system. To this end, each water supply system needs to continuously improve its automation level. The functions of automatic control system are : (1) The duty officer monitors the main equipment and processes and water quality parameters of the water plant through computer in the central control room and performs data management. (2) Water distribution, chemical dosing, constant water level of filter and backwashing are all carried out automatically, and the duty officer can also intervene in the central control room. (3) The water supply network information management system and business billing system are intelligent and networked. All of the above are based on the advanced and reliable basic automation components; otherwise, comprehensive automation would be baseless. This article provides a brief introduction to the principles, current status, and applications of basic automation components such as soft starters, frequency converters, and brushless and ringless starters for technical personnel to refer to.