This article outlined the background and the concept of health decision support system (HDSS), discussed its application status in medical service, hospital management, public health management and other fields in the following four developed countries: United States, UK, Canada and Australia. It also introduced the main functions of MYCIN, CPOE, DHCP, Panorama etc., and summarized the above four countries’ successful experiences, including, actively promoting the application of decision support technology in health field through closely combining with the practical needs, valuing evidenced-based resources development and repository research, making scientific health policy to guide the orderly development of decision support systems, and strengthening the construction of E-health infrastructure and core systems, in hopes of providing reference for the development of health decision support system in China.