The invention discloses a three-degree-of-freedom spatial parallel mechanism which comprises a regular triangular moving platform and a regular triangular fixed platform, wherein the moving platform and the fixed platform are connected through three branch chains, so as to form the shape of a triangular pyramid frustum; and the three branch chains are symmetrically distributed in a triangular manner. The three-degree-of-freedom spatial parallel mechanism disclosed by the invention is equipped with the three branch chains and has the characteristics of being high in bearing stiffness, high in accuracy and high in flexibility; and equipment related to motion simulation, exercise rehabilitation and the like can be designed based on the three-degree-of-freedom spatial parallel mechanism.