In order to effectively solve the concrete construction problem of the critical component size between mass concrete and none mass concrete, studied the temperature crack reasons of mass concrete, and proposed novel construction methods of "soft bag big mold side thermal insulation and moisture preservation ". By the construction practice of Liuyang waterfront mountain city project, proves that the method has obvious effect to control concrete temperature stress, and it is simple, small investment and has significant economic benefits, worthy of the actual promotion.