Abstract: A structure design scheme for a new type virtual axis machine tool(VAMT) is proposed in this paper. The scheme utilizes a 4-dof spatial parallel mechanism as main feed mechanism, assists with a dual-direction movable worktable to realize multi-coor dinates NC machining. The VAMT enjoys many advantages over its conventional counterparts:large workspace, good dexterity, position decoupling with orientation et al. The DOF of main feed mechanism is calculated, approach for inverse displacement analysis is given, and closed equation of forward displacement analysis is derived. Anumeric example is given for illustration.