The invention relates to a three-freedom-degree parallel mechanism. The three-freedom-degree parallel mechanism has the advantages of being simple in structure, high in rigidity, convenient to manufacture and install and capable of easily achieving
motion control. According to the technical scheme, the three-freedom-degree parallel mechanism comprises a rack, a movable platform and three branches connected between the rack and the movable platform, wherein the first
branch and the second
branch are symmetric to the movable platform, and the third
branch sequentially comprises a universal hinge, a sliding pair, a guide rod, a first rotating pair, a connecting rod and a second rotating pair. The three-freedom-degree parallel mechanism is characterized in that the first branch and the second branch respectively and sequentially comprise a sliding pair, a guide rod, a first rotating pair, a first connecting rod, a second rotating pair, a second connecting rod and a universal hinge or respectively and sequentially comprise a first rotating pair, a sliding pair, a guide rod, a second rotating pair, a connecting rod and a universal hinge or respectively and sequentially comprise a rotating pair, a first connecting rod, a sliding pair, a guide rod and a spherical hinge or respectively and sequentially comprise a sliding pair, a guide rod, a first rotating pair, a first connecting rod and a spherical hinge.