Based　on　the　classical　electromagnetic　radiation　theory,　the　spectral　characteristics　of　90°　linear　Thomson　scattering　with　linearly　polarized　few-cycle　laser　pulses　were　obtained.　The　research　results　showed　that　the　fewer　the　cycle　number　of　the　few-cycle　pulse　was,　the　wider　the　scattering　spectrum　and　the　weaker　the　center　intensity　of　the　spectrum　were,　and　the　spectral　width　was　proportional　to　the　square　of　the　electronic　relativity　factor,　as　well　as　the　incidence　pulse　frequency.　The　spectral　intensity　was　proportional　to　the　square　of　the　product　of　normalized　light　field　intensity　and　electronic　relativity　factor.　The　carrier-envelope　function　could　widen　radiation　spectrum　further　and　make　the　spectrum　symmetry　better　and　eliminate　the　oscillation　of　spectrum.　The　spectral　intensity　decreased　with　the　increase　of　the　carrier-envelope　offset　phase　first,　and　then　increased　and　it　decreased　with　the　electron　initial　phase　being　enhanced.