The invention provides a drying heat pump system adopting an air energy open type humidity-eliminating mode and a closed type dehumidifying mode. The drying heat pump system comprises a first heat exchange region with an evaporator, a second heat exchange region with a condenser, a third heat exchange region, a compressor region and an air return region, wherein a first air flue for enabling the compressor region to communicate with the second heat exchange region and a second air flue for enabling the first heat exchange region to communicate with the air return region are arranged in the third heat exchange region; the first heat exchange region is equipped with a fresh air door and an air outlet; a hot air outlet is formed in the second heat exchange region; an air return hole is formed in the air return region; a first switching door capable of opening a channel between the two regions and the air outlet is arranged between the first heat exchange region and the compressor region; and a second switching valve capable of opening a channel between the two regions and the second air flue is arranged between the second heat exchange region and the air return region. With the adoption of the drying heat pump system, switching between the air energy open type humidity-eliminating mode and the closed type dehumidifying mode can be realized at different time quantum for material drying, defects of single-mode drying are avoided; and the drying heat pump system has wider drying process adaptation and realizes efficient energy-saving and drying performances.