The invention discloses an integrated machine for constant-temperature heating and charging before forging of a valve. The integrated machine comprises a heating furnace, a charging machine and a controller, wherein the heating furnace comprises a furnace chamber feeding and returning mechanism and a furnace chamber; a furnace chamber feeding pipe is arranged on the furnace chamber feeding and returning mechanism; the charging machine comprises a lifting mechanism, a pushing mechanism, a feeding mechanism and a grabbing manipulator; the feeding mechanism comprises a feeding chain; the temperature in the furnace chamber is stabilized at a preset temperature under the control of the controller, a bar material is lifted to the pushing mechanism by the lifting mechanism, is pushed by the pushing mechanism to the feeding mechanism and is drawn by the feeding chain on the feeding mechanism to move to a position where the grabbing manipulator can conveniently grab the bar material, and then the bar material is grabbed by the grabbing manipulator and moved to the furnace chamber feeding pipe on the furnace chamber feeding and returning mechanism and is finally pushed by the furnace chamber feeding and returning mechanism to enter the furnace chamber for constant-temperature heating. The integrated machine automatically charges the material to the furnace chamber by the aid of the charging machine matched with the heating furnace and is very convenient to use.