The invention relates to a cocoon drying machine, in particular to an incremental hot air circulation cocoon drying mechanism and a method thereof. The incremental hot air circulation cocoon drying mechanism mainly solves the technical problems that incremental circular heating cannot be carried out by a cocoon drying machine, the effects of quick warming and energy saving cannot be realized, drying is relatively nonuniform and the production quality of cocoons is relatively poor in the prior art. The incremental hot air circulation cocoon drying mechanism comprises a plurality of layers of cocoon conveyor belts, wherein a cocoon hopper is arranged above the cocoon conveyor belt positioned on the uppermost layer; a first heater and a second heater are arranged at one end of each cocoon conveyor belt from top to bottom; a fourth heater and a third heater are arranged at the other ends of the cocoon conveyor belts from top to bottom; an air outlet of the first heater and an air outlet of the second heater align to a return air inlet of the fourth heater and a return air inlet of the third heater respectively; a return air inlet of the first heater aligns to an air outlet of the third heater; an air outlet of the fourth heater aligns to the cocoon hopper; the upper part of the cocoon hopper is connected to the return air inlet of the third heater through a circulating air passage.