Abstract: Making capital investment decision is an important part in enterprise’s financial management. Investors use capital budgeting methods to analyze the feasibility of the project, and make decisions. There are many preconditions or hypotheses in these methods of capital budgeting, and reasonable assumption is necessary in investment decision, which can simplify the calculation and analysis process, but we have find such problems which are at variance with the theories in practice, that is relation to the reasonability of the assumption in capital budgeting methods. This paper discussed the feasibility and reasonability of some common assumptions of investment decision, aiming at make better service for investment decision.

Key words: hypothesis of investment decision