A low-cost and miniature dissolved oxygen（ DO） sensor is researched and fabricated based on fluorescence characteristic of oxygen sensing membrane. Traditional oxygen sensing membrane preparation scheme is optimized

and the excellent one can be indentified by examining its light transmission features. Influences of water temperature and soaking time on intensity of fluorescence emission of sensing membrane is investigated.Based on it

an unique sensor probe with its end face at an angle of 45° is designed

which can effectively reduce interference from bubbles in water on DO measurement. Experimental results show that the DO sensor can accurately measure oxygen concentration of water under test at a range of 0

20 mg / L

with the measurement error of ± 2 % and detecting precision of ± 0. 1 mg / L

which has a good application prospect in many areas

such as industrial and agricultural production

water quality monitoring and aquaculture etc.