The invention discloses a device for transmitting data from an input device to a computer in a bidirectional radio frequency (RF) mode and also a method thereof. The data transmission device comprisesan emitting component arranged in the input device, a coder, an RF signal emitting circuit, a receiving component arranged in the computer, an RF signal receiving circuit and a decoder. With the method, under normal communication conditions, data are transmitted from an input device (e.g. a keyboard, a mouse, or a touch pad) to a computer through bidirectional single channels so as to lower powerconsumption and obtain higher transmission rate; in addition, if interfered, the device can automatically judge the severity of the interference and determine whether to adopt frequency hopping bidirectional multiple channels to accurately transmit data from the input device to the computer.