The invention provides a proof stick replacement device and an automatic steel making system, and relates to the technical field of smelting. The proof stick replacement device comprises a proof stickpositioning mechanism, a proof stick clamping and rotating mechanism and a proof stick pushing set. The proof stick positioning mechanism is used for containing a proof stick. The proof stick clamping and rotating mechanism is arranged on the side, in the width direction, of the proof stick positioning mechanism and used for clamping and horizontally putting the proof stick vertically put in theproof stick positioning mechanism. The proof stick pushing set is arranged on the other side, in the width direction, of the proof stick positioning mechanism and used for linearly pushing the horizontally-put proof stick in the length direction of the proof stick positioning mechanism. According to the technical scheme, the proof stick can be automatically mounted, and a large quantity of manpower and material resources can be saved.