When the storage tank is covered with soil, the tank body may be deformed and leak due to soil pressure. Therefore, it is particularly important to adopt reliable online monitoring technology for tank leakage to ensure the safety of storage tank production. To solve the problems of low positioning accuracy, slow response time, and small monitoring range in the current storage tank leakage safety monitoring, this paper adopts a new generation of weak reflection grating arrays (FBGs) dual-wavelength wavelength division/time division hybrid multiplexing networking technology to achieve full time, full area online monitoring of the surface temperature of overburdened storage tanks. The temperature measurement accuracy of the FBGs array is ±1 °C, and the spatial resolution of the sensor is 1 m. After two months of data monitoring and high-pressure water filling experiments on the soil-covered storage tank, the long-term stability and reliability of the sensor in the soil-covered situation were verified. The results show that the application of FBGs to storage tank monitoring will effectively improve the production safety of storage tanks and has great value for promotion and application.