With the rapid development of advanced nuclear energy technologies represented by small modular reactors, the design of reactor structures has tended towards compactness, modularity, and lightweightness. Additionally, operating temperatures have increased, radiation protection requirements have become more stringent, and there is a greater emphasis on environmental friendliness. As a result, traditional radiation shielding materials can no longer meet the radiation protection needs of advanced reactors, and there is an urgent need to develop new, engineerable, structural–functional integrated radiation shielding materials suitable for high-temperature environments. Therefore, a gamma-ray shielding composite with WC particles-based and high entropy alloy (HEA) as binder phase was designed and successfully prepared by hot pressing sintering method. In this research, the effects of WC particle size, preparation process parameters, and high-entropy alloy composition on the mechanical and shielding properties of the composite materials was studied. The results show that the composite had the best bending strength and linear attenuation coefficient when the particle sizes of 0.5 μm and 3 μm were mixed. Further study shows that the composites with excellent comprehensive properties can be obtained by using 5 wt.% AlCrFeNi quaternary Co-free HEA as binder phase, which was prepared by hot pressing sintering at 30 MPa and 1500 ℃ for 60 min. Hardness and flexural strength of the specimen are 82.42HRA and 1020 MPa, respectively. Meanwhile, its linear attenuation coefficient and mass attenuation coefficient are 0.71 cm−1 and 5.83 × 10−2cm2/g respectively, which has obvious advantages compared with traditional plumbum, tungsten and other gamma-ray shielding materials. This new gamma-ray shielding composite material can provide a new efficient solution to solve the radiation shielding in confined space in small modular reactors.