Abstract: A response reading method and a data transmission system are provided. The method includes, transmitting a first operation command sequence corresponding to a first temporary file to a memory storage device by a system, where the first operation command sequence instructs a smart card to execute a first operation. The method also includes, executing a first writing operation of a first dummy file to update first data in a cache memory. The method further includes, executing a response reading operation corresponding to a second temporary file by the system to read a response of the smart card corresponding to the first operation command sequence.