Distortion　induced　by　non-uniform　thermal　gradients　is　one　of　the　major　constraints　in　wire　and　arc　additive　manufacturing.　A　novel　flexible　multi-point　support　fixture　(FMSF)　featured　by　reconfigured　working　surface　and　controllable　restraining　force　is　developed　as　an　in-process　distortion　control　technique.　FMSF　allows　the　distortion　to　be　suppressed　by　adjusting　the　restraining　force　imposed　onto　the　substrate　dynamically　as　the　number　of　layers　increases.　Both　simulations　and　experiments　are　conducted　to　verify　its　effectiveness　and　compare　it　with　other　common　restraint　forms　including　clamping　and　pre-springing.　The　multi-layer　deposition　results　show　that　a　reduction　of　96.3%　in　angular　distortion　and　86.5%　in　longitudinal　bending　distortion　are　obtained　with　FMSF,　which　exhibits　great　superiority　over　clamping　and　pre-springing.