A data protection method adapted to a rewritable non-volatile memory module having a plurality of physical blocks is provided. The data protection method includes following steps. If the rewritable non-volatile memory module is powered on, a power-off period from last time the rewritable non-volatile memory module is powered off till present is obtained. If the power-off period is longer than a time threshold, whether each physical block satisfies an update condition is determined according to a block information of the physical block. An update procedure is executed on the physical blocks that satisfy the update condition. The update procedure is configured to read data from a physical block and rewrite the data into one of the physical blocks. Thereby, data in the physical blocks is protected from being easily lost, and the lifespan of the rewritable non-volatile memory module is prolonged.