The invention discloses an integral energy-saving hot flash-drying system which comprises a heating and dehumidifying device, a forced cooling device and a heat pump, wherein the heating and dehumidifying device comprises a heating mechanism and a dehumidifying turbine; a fresh air inlet pipeline of the heating mechanism passes through a processing zone of the dehumidifying turbine and then is communicated to a fresh air supplementing inlet of the heating mechanism, and a regeneration zone of the dehumidifying turbine is communicated with a smoke excess heat recycling mechanism. The invention aims at the defect that higher temperature and air volume are required to meet flash-drying dehydration requirements because the moisture content of fresh air dehumidified by a cold water coil of the present flash-drying system is still relatively high, a dehumidifying turbine type dehumidifying method is used in a fresh air supplementing mechanism of the flash-drying system, the flash-drying temperature is reduced, the consumption of natural gas is reduced, the air volume is lowered, and the energy consumption of a fan is also lowered; at the meantime, a quaternion heating box can be made smaller, so that the initial investment is reduced.