The invention relates to a redundant drive three-freedom-degree parallel mechanism with double motion platforms. The aim is that the mechanism has the advantages that a kinematic model is simple, calibrating control is easy and the mechanism is convenient to manufacture and install. The technical scheme is that the redundant drive three-freedom-degree parallel mechanism with the double motion platforms comprises an upper platform, a lower platform, a machine frame and four independent telescopic adjusting branches. The redundant drive three-freedom-degree parallel mechanism is characterized in that every moving pair comprises a sliding block in sliding fit with a guide rail, a driving device of every moving pair is a screw rod mechanism driven by a motor, the screw rod mechanism comprises a screw rod driving the sliding block through a thread fit structure, and the axis of the guide rail and the axis of the screw rod are perpendicular to the ground.