The economic parameters of the power plant such as interest rate, construction escalation rate, fuel escalation rate, maintenance escalation rate and discount rate can affect the annuallevelized cost considerably and change the economic range of the power plants. Determining the values of the economical parameters in the future is very difficult, especially in developing countries like Vietnam. For this reason, the analysis of the changing rates of the mentioned values is of great importance for the planners ol the additional capacity. In this study, the changing rates of the economic parameters in Vietnam that influence the annual levelized cost of the steam turbine power plant is discussed. The steam turbine power plant considered for the electricity generation sector and the economic parameters dominating the plant are determined. It is clearly seen that the annuallevelized cost for steam turbine power plant varies with the economic parameters. The annuallevelized cost increases when the construction escalation rate and the interest rate increase, however, the annual levelized cost more rapidly increases with the increase of interest rate. It is also shown that the interest rate affects considerably the plant having the great capital cost and long construction duration, therefore, the plants having a lower capital cost and a shorter construction time are influenced much less. The annuallevelized cost is also affected by the fuel price escalation rate, but this rate has the least effect of all the economic parameters. With the increase of discount rate, the annuallevelized cost increases, however, it is known that when the load factor is lower than 10 percent, the annuallevelized cost is low as the discount rate is high. Therefore, the authors do not need a high discount rate for the load factor greater than 10 percent. The results show that the economic parameters variation has to be taken into consideration in electricity generation planning.