Abstract-As FAT32 file system implemented on Windows is not open source, this paper tries to analyze its allocator strategy by analyzing the structure and principle of DBR, FSINFO sectors on FAT32, as well as the source code of FAT32 file system implemented on Linux. Then using these theories together with hypotheses to do massive experiments of creating, copying and deleting files on devices with different format type to help analyze it in depth. Declare the differences by comparing it with three common allocator strategies, finally help researchers and users to understand FAT32 file system better and protect their data better.