The invention discloses a device for measuring spatial motion with six degrees of freedom and a dynamic measuring method. A fixed platform (1) of the measuring device is provided with six Hooke hinges (2), and a moveable platform (10) is arranged above the fixed platform (1). The moveable platform (10) is provided with six ball hinges (9) which are respectively connected with the corresponding six Hooke hinges (2) through branched chains. A revolute joint (6) of each branched chain is provided with a spiral coder (5). The dynamic measuring method comprises the steps of establishing a coordinate system, measuring an angle-time curve of relative motion of upper and lower support rods of the revolute joint (6) by the spiral coders (5), so as to obtain the law of motion with the spatial six degrees of freedom of an object measured by a positive solution of the angle-time curve of the spiral coder (5) and the like. The device and the method not only measure the motion with the six degrees of freedom simultaneously, but also ensures the accuracy of measuring results, and have the characteristics of being good in flexible, strong in adaptation, wide in measuring range, high in accuracy and the like.