The utility model discloses a three side chain 6 -degree of freedom robot mechanism that connects in parallel, include quiet platform, move the platform and connect at the quiet sport branch that three structure is the same who moves evenly distributed between the platform, its characterized in that each sport branch includes: one five revolute pair planar motion chain and upper and lower two hookes hinge, five revolute pair planar motion chains comprise plane pentagon and five revolute pairs that four lower connecting rods and quiet platform are constituteed, and wherein, quiet platform is fixed to include two side links and two middle poles as the frame in four lower connecting rods, and the axis of five revolute pairs is parallel to each other to the plane that equal five revolute pair planar motion chains of perpendicular to are constituteed, the rotation of two side links is as the drive of this mechanism in the five revolute pair planar motion chains, the articulated department at five revolute pair planar motion middle -of -chains, two poles is installed to the hooke hinge down to go up the connecting rod through one and connect with last hooke hinge, go up the hooke hinge while and move the platform and be connected.