Memory storage device and memory controller and data writing method thereof

The invention discloses a memory storage device and a memory controller and a data writing method thereof. The memory storage device comprises a connector, a reproducible nonvolatile memory module, a second scratch pad memory and the memory controller with a first scratch pad memory. The memory controller is used for receiving a writing command and write data and temporarily storing the write data into the first scratch pad memory. The memory storage further replicates the write data into the second scratch pad memory and writes the write data into the reproducible nonvolatile memory module according to the writing command. Moreover, the memory controller is further used for judging whether a program error is generated when the writing command is executed and reading the write data from the second scratch pad memory and executing the writing command again when the program error is generated. Therefore, the writing speed of the memory storage device can be effectively promoted.