Abstract: To research temperature drop law of oil stored in large-scale tank, temperature monitoring points are laid out at different locations of tank based on heat transfer performance of floating roof tank and temperature monitoring device for large-scale tank is developed. This device is based on PC/104 embedded host system and DS18B20 digital temperature sensor and adopts unibus protocol, which not only changes conventional cabling form, but also greatly saves installation cost. This device can be used to realize field storage of data and multi-form remote transmission.