In recent years, the fiber optic temperature measurement system has been widely used in the field of power generation. This Paper introduced the working principle of fiber optic temperature measurement detector, and presented an application example of TFRC128-EFMS fire monitoring system in a 2×1 000 MW power plant. The debugging results of fire alarm system show that all kinds of performance are good and each index can meet the requirements. So the fiber optic temperature measurement technique should be widely applied in power plants.