The embodiments of the present invention provide a broadband transmitting device. The broadband transmitting device includes a first radio-frequency switch module, a high-frequency amplifier, a low-frequency amplifier, a high-pass filter, a low-pass filter, and a second radio-frequency switch module. According to the broadband transmitting device of the invention, radio frequency signals are gatedto the corresponding high-frequency or low-frequency power amplifier through the first radio-frequency switch module, and therefore, broadband segmented amplification and filtering are realized, andthe power amplifier can realize excellent matching performance and gain flatness in all frequency bands; and thus, the second harmonic suppression of the broadband transmitting device is improved, andthe interference of the device on other users in other frequencies and wide-frequency bands can be effectively reduced.