A novel form-stable phase change material (FSPCM), namely, diethylene glycol hexadecyl ether-grafted graphene oxide (E2C16-g-GO), was fabricated by an esterification reaction. As E2C16 was modified with GO for the first time, the optimal E2C16 and GO reactant ratio and reaction time were determined to be 6:1 and 6 h, respectively. The successful synthesis and chemical structure of E2C16-g-GO were confirmed by various spectroscopy and microscopy techniques. The thermal properties and stability of E2C16-g-GO were characterized by DSC and TGA. The melting and crystallization points of E2C16-g-GO are 43.3 degrees C and 29.4 degrees C, respectively. The latent heats of melting and crystallization are 70 and 72 J/g, respectively. The degradation temperature of E2C16-g-GO is approximately 20 degrees C higher than that of E2C16, indicating that it has good thermal stability. Furthermore, E2C16-g-GO exhibits good shape-stability and excellent thermal reliability and structural stability, indicating that it is a promising FSPCM for energy storage applications.