The dynamics equation of a space parallel mechanism was established on the basis of Newton-Euler approach to explore the rigid-body dynamic modeling of the 4-UPS-UPU 5-DOF parallel mechanism. The forces of driving limbs and a moving platform for the parallel mechanism were analyzed, and the rigid-body dynamics equation of 4-UPS-UPU parallel mechanism was derived by Newton-Euler approach. Then, Matlab was used to calculate numerically the driving forces for the moving platform with or without loads, and the driving forces of five driving limbs were obtained respectively. Finally, the ADAMS was taken to perform the dynamic simulation for a virtual prototype of the parallel mechanism. Research results indicate that when the parallel mechanism moves a circle with a radius of 0.01 m in the Z axis at a 0.95 m plane, the driving force of the limb 1 is the maximum, the maximum value without the load is -760.6 N, and that with the load is -889.7 N. The theoretical calculation results are greatly consistent with that of virtual prototype simulation, which verifies that the rigid-body dynamics analysis is correct. The research not only provides a theoretical basis for manufacture of 4-UPS-UPU parallel mechanism, but also suggests a way to the rigid body dynamics modeling for other spatial parallel mechanisms.