<p indent="0mm">Human beings cannot live without water. As the living space of human beings, architecture cannot do without water. The water quality safeguard of healthy buildings includes water quality safeguard for municipal water supply and secondary water supply systems. Compared with municipal water supply system, water quality assurance of secondary water supply system is often ignored in people’s traditional concept, while the latter is more likely to cause water quality deterioration. Healthy building is a building that can provide healthier environment, facilities and services for building users and promote their physical and mental health. The water supply system of a healthy building should be able to provide safe and high quality water to building users. Water quality safeguard technology is the key support to achieve the above goals. This paper mainly analyzes and introduces the water quality safeguard for secondary water supply system of healthy buildings. The water quality guarantee measures that can be adopted in the system setting, operation and maintenance of healthy buildings are summarized into three main aspects: Prevention of water quality deterioration, water quality monitoring and water treatment. Prevention of water quality deterioration is the first line of defense to ensure healthy building water quality. Water quality deterioration is usually caused by two factors: Microbial breeding in the water and pollution in the water supply. Problems such as long storage time, inadequate cleaning and maintenance of storage facilities, improper selection of water pipes for transmission and distribution, and insufficient water supply temperature of centralized domestic hot water system will lead to the breeding of bacteria and other microorganisms in water. Problems such as improper installation of water storage facilities and wrong connection of pipes in quality water supply system will lead to water pollution. The prevention of water quality deterioration of secondary water supply system mainly involves water storage facilities, water supply pipes and central domestic hot water system. The water quality online monitoring system can detect water quality indicators in real time through the configuration of online testing equipment, and then upload the monitoring data to the remote data management platform, and finally analyze the monitoring data and alarm the accident by the data management platform. Online monitoring of water quality can help managers to know the abnormal changes of water quality in time, so as to take effective measures to avoid the increase of water quality deterioration accidents. The main technologies and management measures involved in water quality monitoring include water quality online monitoring, regular testing and monitoring results publicity. Water treatment is the ultimate defense of healthy building water quality. Healthy building water supply system can adopt water treatment technology to ensure the safety, improvement and improvement of water quality. Water treatment technologies that can be used in healthy buildings generally include disinfection, filtration, softening and other major water treatment technologies and direct drinking water treatment systems. Different buildings can make economic and technological comparison according to the user’s demand for water quality, and finally choose a reasonable one or a variety of comprehensive water treatment technology. The aim of this paper is to provide suggestions and broaden ideas for the water quality safeguard of healthy buildings, and help health building users understand health building water quality safeguard.