Abstract: The floatertype measurement devices with their readings recorded manually are still used in many petrochemical enterprises. With regard to their low efficiency, great error and their improbability in implementing automation management and remote control, a new liquid level measuring system with the advanced fiberoptic sensing technology based on the traditional floater level meter is developed. It measures the liquid level of an oil tank by using the principle of force balance, captures and transmits optical signals by means of the fiberoptic sensors, implements optical signal modulation with the selfmade light code disc. Moreover, It was tested in a chemical plant. The testing results indicate that the measurement error is ≤±6 mm，relative error is ＜2% when its measuring range is 0～ 1 000 mm. It is proved that every specification of the system meets the demands of its users and its performance is reliable.