Provided are a semiconductor memory device and a data write and read method thereof. The semiconductor memory device includes a write data controller, an address controller, and a read data controller. The write data controller writes data received with an address to a first memory cell corresponding to the address and simultaneously stores the data in a data register. The address controller decodes and stores the address in an address register. The read data controller outputs data from a second memory cell corresponding to an address received with a data read command if the received address is different from the address stored in the address register, and outputs the data stored in the data register if the received address is equal to the address stored in the address register.