Thermal energy storage with phase change materials (PCMs) is of great concern for energy conservation due to its characteristics of high latent heat and constant temperature during phase transition process. In this paper, binary eutectic mixtures (EMs) using fatty acids including lauric acid (LA), myristic acid (MA), palmitic acid (PA) and stearic acid (SA) with 1-hexadecanol (HD) are produced, and then titanium dioxide (TiO2) is employed to form composite phase change materials (CPCMs) for purpose of promoting the thermal conductivity. The chemical structure, microscopic morphology, thermal property, thermal reliability and thermal stability of these CPCMs are inspected carefully. The results illustrate that TiO2 particles have no obvious aggregation in EMs, and there is no chemical reaction between the components of CPCMs. High latent heats above 200 J/g are achieved with phase transition temperatures at 45.4 °C, 51.2 °C, 55.1 °C and 58.3 °C for individual system of LA-HD/TiO2, MA-HD/TiO2, PA-HD/TiO2 and SA-HD/TiO2 respectively. The prepared CPCMs maintain good performance after 100 thermal cycles. The decomposition of CPCMs is retarded and the thermal stability is enhanced. TiO2 improves the thermal conductivities of EMs, which reach a maximum value of 0.358 W/(m·K). In brief, the CPCMs proposed in this paper possess high latent heat and high thermal conductivity as well as excellent thermal stability and thermal reliability, implying that it has a significant potential for thermal regulation and energy conservation.