The invention discloses a multifunctional ready-to-drink warm and hot dual-purpose phase change thermal storage energy-saving water boiler which comprises a water magnetizer, a cylindrical four-pipe type stacked spiral pipe phase change heat exchanger, a boiled water heating tank, a boiled water storage tank and a warm water tank.The phase change heat exchanger comprises a low-temperature water inflow main pipe, a low temperature water backflow main pipe, a boiled water inflow main pipe and a warm water outflow main pipe.The water boiler aims to solve the problems of frequently-seen repeatedly-boiled water, unboiled water and boiled water, inconvenience in drinking very hot water and energy waste and the like in a conventional water boiler.The water boiler can provide hot water and warm boiled water for users on various sites and save energy and is environmentally friendly, convenient and healthy; a water level, temperature and water flow probe multi-group signal collection and warning system is adopted to intelligently control a water pump and a solenoid valve and the like.The water boiler is high in practicality, efficient conversion of warm water and hot water is achieved on the premise of energy saving, and convenience is provided for users.