The invention discloses a high-pressure water mist spray head fog flux test method, which comprises the following steps: step 1, installing a plurality of spray heads into a test device; step 2, selecting four spray heads distributed in a cuboid shape in the test device, arranging 4 x 4 water collecting discs below the spray heads, wherein the size of each water collecting disc is 36cm x 28cm x 8cm, the longitudinal distance between the water collecting discs is 72cm, the transverse distance between the water collecting discs is 64cm, the water collecting discs at vertexes are positioned rightbelow the spray heads, and the arrangement height of the spray heads is 6.5m; step 3, starting timing when water mist falls to the water collecting discs after top spraying is started, and recordingthe spraying time for 5 minutes by a stopwatch; and step 4, collecting and measuring water collection amount by using a measuring cylinder, and dividing the water collection amount by time and area tocalculate the fog flux. According to the high-pressure water mist spray head fog flux test method, the fog flux of the spray head can be effectively detected by using a water collection method through the arrangement of the steps 1 to 4.