This invention relates to a system for measuring water quality using a smartphone, and more particularly to a system for measuring water quality using a smartphone, in which, to solve problems of hand-operated and manual water quality measurement methods and in order to increase reliability and accuracy, a water quality meter and a smartphone, which mutually communicate with each other, are utilized, and also, the smartphone is provided with a memory unit, a calculation unit, a GPS unit, etc., thus enabling water quality to be measured in real time and water quality data to be stored and transferred to the outside, so that reliability and accuracy of the measured water quality data may be improved.