A data writing method is provided. The method includes receiving a first write command and first data corresponding to the first write command from a host system, wherein the first write command instructs to store the first data into a first logical address; copying the first data into a register, responding to the host system that the first write command is completed, and starting to execute a first program operation to program the first data into a first physical page; and in response to determining that the first program operation is failed, reading the first data from the register according to a logical to physical addresses mapping table and mandatorily programming the first data into a second physical page.