Metal-organic framework (MOF) is a new generation of crystalline porous materials that are characterized by simple synthesis conditions, diverse structure, and modified pore surface. MOFs suffer from low mechanical strength and poor chemical stability, limiting their development and application. The construction of MOF composites can effectively compensate for these defects while introducing new properties and functions. Compared with single materials, MOF composites exhibit greater specific surface area and porosity, stability, and catalytic performance and other functions. This review summarizes the synthesis methods and different types of MOF composites. Recent developments on the function and application of MOF composites in chemical sensors are presented. Finally, the prospects for the future development of MOF composite-based sensors are emphasized in many cases.