In ice storage technology, making ice slurry by direct contact solid liquid phase change and cool supply by direct pumping of ice water two phase flow is one of the development tendencies in disstrict air conditioning with ice storage. The better understanding on heat transfer characteristics of ice storage system is the base for designing and optimizing the ice storage tank. The paper reviews the current development in direct contact solid liquid phase change heat transfer in ice storage and introduces the method of enhancing ice making and the current research about the ice storage system. Considering the current situation in research and application, the paper proposes some unsolved fundamental heat transfer problems in ice storage technology.