This paper analyzes a unitized participating life insurance endowment policy，paid by annual premiums，in which a minimum return，an annual bonus and a terminal bonus are guaranteed to the policyholder．Moreover，the policy under scrutiny is characterized by the presence of a surrender option．Compared with other participating life insurance policies，the most important feature of this policy is the terminal bonus option．However，current researches on pricing of this policy rarely considered the terminal bonus option together with the other embedded options．The aim of the paper is to give sufficient conditions under which there exists a fair premium and the pricing of terminal bonus option is also well considered．This premium is implicitly defined by an equation based on the classical actuarial pricing technique and contingent claim pricing theory．An iterative algorithm based on Monte Carlo simulation method is then implemented in order to compute it．Based on this valuation approach，the paper also provided both theoretical and numerical analysis of the effect that mortality rate，guarantees，annual bonus，terminal bonus and surrender have on the value of terminal bonus option．The findings are as follows: Firstly，a terminal bonus option has a higher value than a surrender option and the terminal bonus decreases the incentive to surrender． Secondly，the value of terminal bonus option tends to go up along with any increase in mortality rate，minimum guaranteed interest rate or terminal bonus ratio and any decrease in risk free rate or volatility would also cause the value of terminal bonus option to increase．