The role of fly ash in concrete become impotant with finding the charateristics of fly ash in which it is used as cement replacement material. An experimental study is carried out to investigate the characteristics of concrete containing fly ash. The loss of slump and air content of fly ash concrete tested up to 120 minutes are lower than those of ordinary concrete, but the setting time and bleeding are increased with increasing fly ash content. The compressive and tensile strength of fly ash concrete are slightly lower than those of ordinary concrete between 7 and 28 days, however, the long-term (at 180 days) compressive strength of fly ash concrete is significantly higher. In addition, fly ash reduces the heat of hydration and peak of temperature rise in concrete.