This work investigated the time dependent mechanical properties of bovine enamel. The cubic specimens of enamel were prepared from bovine incisors and the ramp-hold compression tests were performed to acquire the stress-time and strain-time relation of enamel under compress load. In this study, enamel was considered as linear viscoelatic material. The long-term elastic modulus of enamel was evaluated from the stress and strain relations at the end of ramp-hold tests and the relaxation behaviour of enamel was estimated from the normalized stress-time curves of ramp-hold tests. The relaxation coefficients and characteristic times of linear viscoelastic model were obtained by using iterative inverse finite element method. The results show that a linear viscoelastic model with 3 relaxation time constants can well describe the time dependent behaviour of bovine enamel under uni-axial compression load.