Abstract: In this paper,the additive time effect was introduced into the vacation queueing system.From the view of customers’ decision,two entry probabilities in the equilibrium and social optimality are obtained to present the relationship between two probabilities which shows that more concerns to personal benefit will induce to a heavier system load and affect the social benefits.To parallel personal and social benefits,the fixed entry fee is given based on the ex-ante externalities and three variable entry fees are presented from the view of ex-post externalities to enable the different companies to apply different fee mechanisms.

Key words: Vacation queue,Additive time,Entry probabilities,Social optimality,Ex-post fee