The invention discloses a solar water tank semi-finished product air-tightness detection apparatus with an obvious effect, and relates to the technical field of solar energy. The apparatus comprises abase plate, the left side and the right side of the top of the base plate are respectively and fixedly connected with a support, the tops of the supports are movably connected with a water tank, thetop of the base plate is fixedly connected with a filter case and an air pump in sequence from left to right, an air outlet of the air pump communicates with an air-outlet pipe, the left end of the air-outlet pipe communicates with the right side of the filter case, and the front side and the rear side of the filter case both communicate with a connecting pipe. According to the solar water tank semi-finished product air-tightness detection apparatus with the obvious effect, soldering joints of side surfaces of the water tank can be sealed by employing an elastic rubber tape, if air leakage ofthe soldering joints occurs, air can be concentrated in detection boxes, the leakage can be visually displayed through a first alarm lamp by employing cooperation of hollow metal balls, chutes and conductive blocks, whether the air enters the detection box can be detected, namely, whether air leakage of the soldering joints of the side surfaces of the water tank occurs can be detected, the operation is simple, and the effect is obvious and rapid.