The invention belongs to the technical field of forging, and relates to a method for forging large-size integral titanium alloy frames, which includes: the first step, designing a finish forge piece and an isothermal forging die according to materials, shapes and size of parts; the second step, designing a hammer pre-forging piece and a die drawing and keeping the size of a cavity of the pre-forging piece die and the size of a cavity of the isothermal forging die consistent; the third step, selecting pre-forging piece blank and making a finish forging die and a pre-forging die according to the first step and the second step; the fourth step, processing the blank by means of hammer pre-forging including coating protective lubricant, heating by an electric furnace, holding temperature, forging, subsequent process and the like; and the fifth step, processing the pre-forging piece by means of isothermal die-forging. The method realizes organic combination of hammer pre-forging and isothermal forging, so that the forging cycle is shortened and the heating number is reduced from 5-7 to 2 in isothermal forging.