Quantum microwave-to-optical wave conversion is a key technology for establishing quantum networks and a driving force behind advances in quantum science. This technology has remarkable potential in areas such as distributed quantum computing, remote quantum sensing, and quantum precision measurements. This article provides a systematic overview of the four main experimental platforms for microwave-to-optical wave conversion: electro-optic, atomic, optomechanical, and magneton systems. This article also reviews the physical principles and models underlying these platforms, summarizes the experimental approaches and research advancements achieved using these platforms, and compares their performance based on the photon conversion efficiency, conversion bandwidth, and specific experimental conditions required. Finally, the current challenges and future trends in microwave-to-optical conversion are discussed, along with key issues that must be addressed for applications in quantum information systems.