  We have discussed the vacuum tunnelling in Friedberg-Lee model. The
tunnelling coefficient is derived in the field configuration space by
calculating the transition amplitude using the path integral under the
stationary phase approximation and the dilute instanton gas approximation. By
studying the tunnelling effect between the two degenerating vacuums at the
critical temperature and chemical potential, we find that the system could be
deconfined by tunnelling, which could possibly change the first order
deconfinement phase transition to crossover.
