The invention discloses a stress-strain-electric signal relation-based water surface evaporation amount measurement method. According to the method, a water surface evaporation amount measuring device is adopted; the water surface evaporation amount measuring device is composed of an evaporation pan, a resistance strain gauge and a signal acquisition system; the evaporation pan is obtained by processing stainless steel; the inner diameter of the evaporation pan is 20.0 mm; the height of the evaporation pan is 10.0 mm; the wall thickness of the evaporation pan is 2.6 mm; the resistance value of the resistance strain gauge is 350; the resistance strain gauge is of a uniaxial strain gauge structure; the length of the wire gate of the strain gauge is 1.0 mm; the signal acquisition device is composed of a communication connection cable and a computer terminal; and real-time measurement of water surface evaporation amount can be realized through the device. The method has the advantages of simple principle, convenient operation, high adaptability and accurate and reliable measurement result, and can provide conveniences for the research and application of related fields.