The invention discloses an auxiliary medicine charging device for a triple generation system. The device comprises a heat supply circulating system and a cold supply circulating system through a three-way joint; then, the auxiliary medicine charging device is controlled through an automatic control module; when medicines are needed to charge in a water circulating system of a heat supply system ora cold supply system, an electric butterfly valve on the corresponding side is automatically opened, and the electric butterfly valve on the other side is closed to realize respective medicine charging of the heat supply system or the cold supply system. A SCADA control system and a water quality monitoring device realize automatic medicine charging without needing manual intervention, so that the medicine charging operation efficiency is improved.