Abstract: Contruction technology of 10×10⁴ m³ floating roof tank was introduced in 1985, and at first the construction was completed in Qin Huangdao and Da Qing oil tank farm. Chinese National Petroleum and Natural Gas General Corporation gave command stopping service of all non-metal oil tank because of several and successive fire disasters, replacing with floating roof tank. Two sets of 10×10⁴ m³ floating roof with two disks were completed in Qin Huangdao oil tank farm, meanwhile an automatic fire control system was introduced from Japan. The system is mainly composed of harzard alarm system, industry TV monitoring system, foam auto extinguish system, autospraying and cooling system, control system, and power system. The six systems are decribed respectively. From the point of ignition possibility the discussion was made such as ignition factors in oil tank farm, fire control scope, tank farm administration, floating roof sealing, spraying and cooling, etc, also some improvement was suggested.