Modern　wireless　telecommunication　requires　high　linearity　of　radiofrequency　amplifiers.　Feedforward　technique　is　the　most　effective　and　sometimes　the　only　one　that　can　improve　the　linearity　to　satisfy　the　system　demands.　It　improves　the　linearity　of　an　amplifier　through　the　following　three　steps,　extracting　the　nonlinear　distorted　component　from　the　output　of　the　amplifier,　adjusting　the　amplitude　and　phase　of　this　nonlinear　distorted　component　to　obtain　the　same　amplitude　and　opposite　phase　as　the　distorted　component　of　the　amplifier　output,　and　counteracting　the　distorted　component　by　summing　up　the　adjusted　nonlinear　distorted　component　and　the　amplifier　output.　ADS　is　one　of　the　most　popular　software　for　radiofrequency　circuitry　design.　Its　simulation　results　can　reflect　the　characteristics　of　circuits　correctly.　We　elaborate　the　basic　theories　and　methods　of　feedforward　technique.　Then　we　simulate　a　feedforward　amplifier　by　using　ADS　software.　The　simulation　shows　that　the　third-order　intermodulation　component　has　been　improved　by　more　than　40　dB.　The　result　of　the　present　study　suggests　that　the　effectivity　of　the　feedforward　technique　improves　the　linearity　of　amplifiers.