The application of C35 pumping concrete with high content fly ash in the mass concrete construction was studied.The content of 425 P.O cement in this concrete is 330 kg/m 3,and fly ash is 130 kg/m 3.The results show that by using this technology,the concrete can meet the requirement of C35 in 60 days,particularly,the heat rise of the mass concrete can be reduced obviously,and the appearance of heat peak can be deferred.