The invention discloses a method and a system for measuring a static contact angle of a weakly hydrophobic surface. The method comprises the following steps: acquiring an image of droplets standing ona to-be-measured weakly hydrophobic surface; determining the outline of the droplets and a baseline of the droplets and the to-be-measured weakly hydrophobic surface according to the image of droplets standing on the to-be-measured weakly hydrophobic surface; determining a position of a three-phase contact point according to the baseline and the outline; identifying a plurality of key points on the outline; performing local fitting on the plurality of key points to form a fitted curve according to a polynomial fitting method; and obtaining the static contact angle of the to-be-measured weaklyhydrophobic surface according to the fitted curve, the baseline and the position of the three-phase contact point. According to the method disclosed by the invention, the local outline of the droplets is subjected to local polynomial fitting by virtue of the image of the droplets dropping onto the weakly hydrophobic surface, and the measured value of the static contact angle of the weakly hydrophobic surface is obtained by local fitting, so that the accuracy of the measured value of the static contact angle of the weakly hydrophobic surface is effectively improved. Moreover, the system disclosed by the invention is ingenious in concept, novel in design and high in practicality.