The invention discloses a temperature control and cracking preventing method for the construction period of flood discharging tunnel lining concrete, that is, water flowing curing and surface heat preservation of heat preservation material covering are combined. Water flowing curing starts from formwork removing, and the end time takes the standard that the difference of the internal temperature of the flood discharging tunnel concrete and the ambient air temperature is not larger than 10 DEG C; the water temperature is dynamically adjusted and controlled, and determined according to the actually-measured internal temperature of the concrete, and it is appropriate that the difference value between the water temperature and the internal temperature is not larger than 10 DEG C; the water flow gives priority to moisture keeping of the surface of the concrete; and surface heat preservation is conducted after water flowing curing is completed till water passes through a flood discharging tunnel and the flood discharging tunnel operates. By establishing an actual model and combining with concrete engineering, the internal temperature and stress change law of the flood discharging tunnellining concrete under a plurality of temperature control and cracking preventing schemes are calculated and analyzed, it is proved that the temperature control and cracking preventing method for the construction period of the flood discharging tunnel lining concrete meets the temperature control and cracking preventing requirements, the flood discharging tunnel lining concrete can be effectively prevented from being cracked, the cracking preventing effect is remarkable, and important reference value for engineering construction of the flood discharging tunnel is achieved.