According to the problem of the existing garbage collection algorithm for NAND flash memory, an efficient algorithm, called AWGC (Age With Garbage Collection), was presented to improve wear leveling of NAND flash memory. A hybrid policy with the age of invalid page, erase count of physical blocks and the update frequency of physical blocks were redefined to select the returnable block. Meanwhile, a new heat calculation method logic pages was deduced, and cold-hot separating of valid pages in returnable block was conducted. Compared with the GReedy (GR) algorithm, Cost-Benefit (CB) algorithm, Cost-Age-Time (CAT) algorithm and File-aware Garbage Collection (FaGC) algorithm, not only some good results in wear leveling have been got, but also the total numbers of erase and copy operations have significantly been reduced.