The invention provides a foldable flex-wing mechanism capable of achieving quick and free folding and unfolding of wings of an aircraft. A miniature screw slider mechanism and a slider-crank mechanism are used in a combined manner, the screw slider mechanism is used for converting rotational motion of a lead screw driven by a steering engine to be rectilinear motion of a slider along the axis of a machine body, meanwhile the slider controls wing skeletons to do unfolding motion, the slider-crank mechanism converts the linear motion of the slider to be rotational motion of the wing skeletons around rotation shafts of the wing skeletons within a certain angle range. Through the design of the stroke of the slider and the length of a crank connecting rod, an unfolding angle is controlled within an ideal range; a screw sliding table mechanism is a labor-saving mechanism with high transmission ratio, and resistance caused when the wings are unfolded can be overcome by a smaller steering engine; the screw sliding table mechanism is placed along the machine body, and one steering engine can synchronously control the wings on two sides to unfold. The wing folding mechanism has the characteristics of reasonable structural layout, simple and artistic appearance, prominent motion performance, simplicity and high efficiency in control, small occupied space, good synchronicity and the like.