In this study, we investigated the influences of abnormal high temperature on growth, yield and physiologically active substances of the strawberry. General strawberry cultivars in the 20℃ growth condition showed much better growth of leaf number, length, diameter along with plant height, compared with those in 22.5℃ or 25℃. But the cultivars of both ‘Sulhyang’ and ‘Mehyang’ showed good growth and development at 25℃ with the roots showing great growth at 20℃. The quality and yield of the strawberry were best in the 20℃ growth condition, but the merchantability deteriorated in the 25℃ high temperature condition. As for the content of the physiologically active substances of the strawberry, it increased at 20℃, the optimum growth temperature, but decreased at 25℃. The physiologically active substances in the strawberry differed among the cultivars, the contents of cyanidin-3-glucoside, cinchonine, ellagic acid and cinnamic acid higher in the ‘Mehyang’, whereas the content of fisetin is higher in the ‘Sulhyang’ cultivar.Consequentially, the high temperature in summer has a negative effect on the physiological active ingredients of the strawberry, which was increased in the strawberry cultivated at proper temperature, and high quality strawberry production was possible.