Abstract: A novel and simple system using Brillouin selected sideband amplification of 11GHz microwave photonic signals is presented. The change of the power of lower sideband of 11GHz microwave photonic signals is analyzed theoretical-ly. The experiment to amplify the sideband of 11GHz microwave photonic signals selectively is performed and 30dB gain is achieved. The measured sideband power as a function of pump power is investigated. The results are well agreed with the theoretical predication.