Provided are a method and device for updating a register. In the method, a first thread for updating a register comprises: reading and storing data of a register to a first memory (201); updating data in the first memory (202); and writing the data in the first memory into the register (203). During execution of the first thread, if a host computer makes a request for writing the register, a first process of the first thread is interrupted and a second thread is executed to write, according to an instruction, data into a second memory (204), and resume the execution of the first thread. Upon completion of the execution of the first thread, the first thread is re-executed. The re-executed first thread comprises: reading and storing the data of the register to a third memory (205); updating, according to the data in the second memory, data in the third memory (206); and writing the data in the third memory into the register (207). The invention can prevent occurrence of a communication failure caused by overwriting of information written into a register by a host computer, thereby ensuring accuracy and reliability of the information written by the host computer.