In ammunition systems, clock mechanism was often used as timing mechanism for ammunition fuze in order to make ammunition work again at a time (or distance). Since shells were in a unique centrifugal environment, clock mechanism was of non-energy storage. Centrifugal force of the projectile was used as the driving force for clock mechanism. Timing principle of clock mechanism was studied and analyzed in this paper. Using three-dimensional modeling software as computer-aided design (CAD) platform for a clock mechanism and MSC.ADAMS (rigid body dynamics simulation software) to simulate and analyze the dynamic characteristics of clock mechanism, rotation speed and rotation time was obtained and also the relationship between the rotation speed and rotation time. Simulation results show that the clock mechanism using centrifugal force as driving force has the time characteristics related to the rotation speed and meanwhile, more stable characteristics of distance.