This paper is devoted to analyzing the connections between entanglement dynamics and classical trajectories with a model of coupled rotor.In the numerical simulation of quantum evolution and the frequency spectrum analysis of classical orbit

we find that entanglement production depends on classical orbit and such phenomenon is closely related to the power spectra of classical trajectories.Classical power spectrum with a more complicated structure corresponds to faster entanglement.With the classical power spectrum

we introduce a new quantity

i.e.

the frequency entropy

to measure the stability of classical orbit.The results show that there is good correspondence between the classical frequency entropies and the maximum von Neumann entropies.