Abstract: In order to meet the rapid development of satellite communication in millimeter-wave, a novel Q band transmission amplicated circuit for space application is presented in this paper. Firstly, the scheme diagram of Q band transmission amplicated circuit is given. The local oscillator-doubler chain and radio frequency-signal amplification circuits have been totally integrated in a single multi-chip module. Then, some measures have been taken to improve the broadband characteristics of designed transmitter. The impedance matching network has been simulated and a new kind of waveguide-coaxial-microstrip probe is optimized to increase its operating bandwidth and decrease the insertion loss with the open stubs. the gain flatness in a wide bandwidth has significantly improved. Lastly, the method to avoid cavity resonance?interference is also introduced. the anti-interference ability of designed circuit is improved by optimizing its DC power supply. This designed Q band transmission amplicated circuit is fabricated and tested. A agreement results have been achieved . It has broad application in the future.