Abstract : Due to the high importance of phase change material (PCM) in engineering applications, huge works devoted to studying this field of science. In this work, a literature review is presented showing the important works in this field and the possible improvements in the thermal performance of the PCM by using various technical methods like using; fins, metal foam, adding additives of high thermal conductivity, and encapsulation techniques. The review also includes some previous studies that surveyed the used material and their engineering applications. The review includes the possible mathematical models that could be used successfully to formulate the thermal behavior of the PCM.