A storage space management method and apparatus, where the method and apparatus are applied to a non-volatile memory (NVM). In a feature set that includes M image features of M idle blocks in storage space of the NVM, an idle block whose image feature is highly similar to an image feature of data to be written into the NVM is determined such that the data is written into the idle block. In this way, wear and energy consumption problems are considered during storage space allocation, and a write operation of an idle block in storage space of an NVM can consume less energy, thereby extending a life span of the NVM and reducing write operation energy consumption.