By combining the existing main types of mercury cadmium telluride (HgCdTe) avalanche photodiode (APD) devices, the current mainstream APD device development route in the world is briefly summarized, and the structures and performance characteristics of major APD devices, including PIN, high-density vertically integrated photodiode (HDVIP) and separated absorption and multiplication (SAM) devices, are analyzed. By comparing the device optimization ideas and performance characteristics of different technical routes, the sustainable development of related devices is prospected. At present, the SAM devices are the structures with the best dark current suppression and high-temperature operation performance among mainstream APD devices, which can achieve high-sensitivity detection under high-gain conditions. This also opened up a new direction for the development of related device processes.