Para-xylene (PX) is a fundamental chemical raw material that is utilized in the production of polyester fibers, dyes, and pesticides. It often existed in mixtures with meta-xylene (MX) and ortho-xylene (OX). Separating PX from xylene mixtures is essential for its chemical application. Due to their highly similar physicochemical properties, the separation and purification of xylene isomers have always been a significant challenge. Among the separation processes, melt crystallization is an effective technology to obtain high-purity PX based on the difference in the melting points of each xylene isomer. It is more efficient and environmentally friendly than other methods. However, the presence of eutectic points necessitates the separation of mixed xylene isomers at significantly low temperatures. The complex-melting crystallization method combines complexation with crystallization processes, which improves the melting points of the isomers to be separated. In this research, the bimetallic halide CuAlCl4 was used as a complexing agent, forming complexes with the three xylene isomers. The complex system had higher melting points and eutectic temperatures than pure xylene system, and the temperature required for crystallization operation was closer to normal temperature. A xylene mixture with a PX content of 74.60% was used as feedstock, and the operating conditions of the complex-melting crystallization process were optimized. In the first crystallization stage, crystallization time was 1.0 h, final crystallization temperature was 5℃, cooling rate was 0.15℃/min, sweating temperature was 36℃, and sweating rate was 1.0℃/min. In the second crystallization stage, final crystallization temperature was 15℃, sweating temperature was 38℃. Through the implementation of two-stage melting crystallization, the purity of PX was successfully increased from 74.60% to over 99.50%, and the yield of PX reached 43.12%. Compared with the pure mixed xylene isomers system, the operating temperature was increased by 20℃ at a similar yield. The results demonstrated that CuAlCl4 was able to separate PX from xylene mixtures and significantly decrease the refrigeration energy consumption during the crystallization process.