Junk data recycling method and storage device

The embodiment of the invention provides a junk data recycling method and a storage device. A data volume of first data at current time and variable quantity of the first data within a preset period before the current time in each segment of the storage device are recorded respectively; according to the data volume of the first data and the variable quantity of the first data in each segment, a predicted value of the first data is calculated; according to the predicted value of the first data in each segment, segments in which junk data need recycling are determined, junk data in the segments with more junk data needing recycling and a lower junk generating speed are recycled preferentially, and therefore efficiency of recycling junk data is improved.