The actual machining process of thinwalled components was simulated in three dimension (3D) by finite element software ABAQUS. The influence was analyzed of support unit of multipoint flexible fixture system of density，spacing and suction of adsorption devices on the machining deformation of thinwalled parts. Sum up the influence rules of three factors on the machining deformation, and the optimal fixture layout reduces the occupation of more resources and allocation time, which puts forward the advices in terms of multipoint flexible fixture system control machine deformation of thinwalled components.