The utility model discloses a new hot air circulatory system for moisture regain, charging equipments, which comprises a heat exchanger, a hot air circulating fan, a hot air circulating main pipe, the heat exchanger is connected in series with the hot air circulating main pipe, an air door supplying new air is arranged on the input of the heat exchanger 2 on the hot air circulating main pipe, one end of the new air supplying air door 4 is communicated with the atmosphere, and the other end is communicated with the input of the heat exchanger 2 on the hot air circulating main pipe; the hot air circulating main pipe 3 is provided with a hot air by-pass pipe 5, the hot air by-pass pipe 5 is bridged connected with the two ends of the input and the output of the heat exchanger, a hot air main air door 6 is arranged between the hot air circulating main pipe, the branch of one end of the hot air by-pass pipe 5 and the new air supplying air door 4, and the other end of the hot air by-pass pipe 5 is provided with a hot air by-pass air door 7; a drain tide air door 8 is arranged on the posterior ventricle of the drum 1. The utility model has the advantages of convenient to exchange the hot air circulating, settling the problem of thermal hysteresis, reducing the scaling of the heat exchanger, enormously improving the hot air heating ability, and reducing the energy consumption.