Multi-principal alloys have exhibited broad structural applications due to their unique microstructure and excellent comprehensive properties, and also been the research focus of structural metallic materials in recent years. As a new type of complex concentrated alloys, there are essential differences between multi-principal alloys and traditional alloys in atomic structure, in which the local chemical short-range order (CSRO) is one special atomic microstructure. The interactions between CSRO and moving dislocations can make a significant influence on the deformation behavior and mechanical properties of multi-principal alloys. Therefore, this paper mainly summarized the progress in the local chemical order in multi-principal alloys, including the formation factors, characterization methods, and effects on deformation behavior and mechanical properties. Moreover, the existing problems and shortcomings in the directly quantitative characterization, quantitative manipulation, theoretical model development and the influence on service performance of chemical short-range order in current research were analyzed and prospected.