A digital signature terminal device and a secure communication method are provided. The digital signature terminal includes a first module and a second module. The first module includes a communication component configured to communicate with outside and includes a central unit. The central unit includes a memory configured to store data received by the communication component. The central unit is configured to receive an operation from a user, and is controlled, in response to the operation from the user, to be simultaneously connected to the second module and disconnected from the communication component or to be simultaneously disconnected from the second module and connected to the communication component. The second module includes a signature component configured to generate a digital signature for the data, and the second module is configured to send the digital signature to the memory.