In　view　of　the　trajectory　adjusting　in　motion　planning　of　wheel-based　robots,　an　improved　trajectory　deformation　approach　is　presented　in　this　paper.　Compared　with　the　original,　this　approach　makes　the　driftless　affine　control　system　converted　to　an　equivalent　drift　affine　system　with　constraints,　and　the　trajectory　satisfies　constraints　in　the　process　of　the　deforming　iteration.　The　improved　trajectory　deformation　approach　can　be　applied　to　the　trajectories　with　arc　length　as　their　parameters,　which　is　more　suitable　for　the　trajectory　generation　and　tracking　in　practical　robot　systems.