This standard specifies the general methods for testing marine instruments in low-temperature environments, aiming to evaluate or determine their adaptability during storage, transportation, and use under low-temperature conditions. The test involves placing samples in a controlled low-temperature environment to simulate harsh working conditions such as polar regions, deep-sea, and frigid sea areas, thereby verifying their structural integrity and performance stability. This testing is particularly crucial for ensuring the reliable operation of marine sensors, underwater robots, and deck equipment in frigid sea regions. The core equipment used in actual testing is a high-low temperature test chamber, which typically has a temperature range from -70°C to above room temperature, featuring precise temperature control and uniform temperature distribution. Some high-end equipment can also integrate a seawater circulation system to more realistically simulate the actual working environment of marine instruments.