Odor pollution has been an environmental issue in the process of global urbanization. Effectively monitoring and identifying  malodorous gases is a critical topic in the fields for environmental management and public health. This paper reviews the current status and development of monitoring technologies for odor. It identifies the sources, physical and chemical properties as well as odor-causing mechanisms of inorganic and organic types of odor gases. Various monitoring technologies are introduced, including sensors, e-nose, mass spectrum and environmental optics. The advantages, disadvantages, and applicable scenarios of each technology are analyzed. Challenges such as monitoring accuracy, sensitivity, sensor selection, environmental interference, cost feasibility, and real-time data processing are also discussed. With the continuous advancement of materials science, artificial intelligence, and system integration technology, monitoring technologies for odor will become more efficient, accurate, and intelligent. They will provide solid technical support for environmental protection and public health.