Optical fiber is the cornerstone of information technology and the foundation for the development of a future intelligent society. As the core material of optical transmission and photonic devices, optical fiber has been widely used in optical communication, laser, optical sensing and other fields. With the continuous expansion of the application field of optical fiber, higher requirements are put forward for the performance and function of optical fiber, and traditional optical fiber materials cannot meet the increasing needs of people. Under this background, multimaterial fibers came into being. Multimaterial fiber is a new type of fiber material developed in recent years, which aims to integrate different functional materials into a single fiber to achieve the multifunction and high-performance of a single fiber, providing new opportunities for expanding the application of conventional optical fibers in many fields. In particular, multimaterial fibers, which have the functions of photoelectric conversion, transmission and collection, have attracted more and more attention due to their wide applications in advanced optoelectronic devices, optogenetics, smart fabrics, multifunctional sensing and flexible wearable electronics. First, the preparation method, structure, properties and application of multimaterial optoelectronic functional fibers are reviewed, and the common preparation method, design strategy and working principle of multimaterial fibers are introduced. Then, the latest progress of multimaterial fiber in the fields of photoelectric detection, biochemical sensing, intelligent fabric and photogenetic neural regulation is summarized. Finally, the development prospect and existing challenges of multimaterial fibers are prospected and analyzed. In this paper, the recent progress of multimaterial fibers in multifunctional sensing applications is reviewed, including the design strategies and the fabrication methods, as well as the research progress. With the development and progress of material processing technology, a variety of functional materials such as metals, semiconductors, crystals, polymers, glass, micro devices, and gels can be integrated into a single fiber or fiber array to achieve multifunction and high-performance, which greatly expands the function and application of traditional optical fibers. While great success has been achieved over the past two decades, the future development of multimaterial fibers still faces several challenges: One is that there is still not enough material that can be integrated into the fiber. The most commonly used method for manufacturing multimaterial fibers is still the thermal drawing, which requires all materials to have matching thermal properties, which limits the choice of materials to make multifunctional fibers. Second, the functional integration of multimaterial fiber is still low. In general, most fibers can only sense one physical parameter, while a few fibers can sense two or more physical parameters at the same time. This limitation may depend on the material composition and the structural configuration of the multi-material fibers. Third, the intelligence of multimaterial fiber is still weak. The integration of multimaterial fiber into the next generation of smart textiles can promote the intelligent process of smart textiles. For example, combining smart fabrics composed of multifunctional fibers with artificial intelligence and big data will revolutionize human health monitoring, such as detecting blood pressure, blood sugar, pH, body temperature, heart rate, etc. At the same time, the mechanical information such as bending, torsion, stretching and rotation of multifunctional fibers can be obtained. Based on the above data and intelligent analysis, the health status of the human body can be accurately assessed at any time, which will greatly change the way people live their daily lives.