Abstract: Ver increasing energy consumption，energy storage techniques are becoming more and more important. It is well known that latent heat storage system (LHTS) is an efficient heat storage system. The phase change materials (PCMs) play an important role in the latent heat thermal storage system. However，some PCMs (especially some organic PCMs) may be limited with low thermal conductivity. Heat transfer enhancement of the PCMs have received great attention as energy saving is becoming more and more important. Various heat transfer enhancement methods are reviewed and discussed，including using metal filler，graphite filler，micro-encapsulation，fins，carbon fibers and multiple change materials. It is reported that the development direction of the PCMs is high thermal conductivity，small weight and low cost.