The invention belongs to the field of air conditioner systems, and particularly provides an air conditioner fresh air system. The air conditioner fresh air system aims to solve the problem that the comfort degree of a user is influenced when an existing air conditioner fresh air system exchanges fresh air in winter. Therefore, the air conditioner fresh air system comprises a fresh air pipeline, afan and a heating device. One end of the fresh air pipeline communicates with the outdoor part, the other end of the fresh air pipeline communicates with the indoor part, the fan is connected with thefresh air pipeline and used for introducing outdoor air into the fresh air pipeline, and the heating device is arranged in the fresh air pipeline and used for heating the air flowing through the fresh air pipeline. According to the air conditioner fresh air system, the heating device is arranged to heat the air in the fresh air pipeline, so that when the air conditioner fresh air system performsfresh air exchange operation in winter, the fresh air can be heated through the heating device, the temperature of the fresh air is improved, the fresh air is close to the indoor environment temperature after entering a room, and the comfort of a user is guaranteed.