Abstract: Adopting the theory of option games, the article explores the issue of the optimal strategic investment decision for enterprises, providing that marke t demand for products and operation cost are contingent. The article, then, make s a thorough analysis of the rules for enterprises  making optimal equilibrium in vestment decsion and discusses the influence of factor volatility on and its cor relation with critical value of optimal investment and equilibrium. The analytic al result is further verified and enriched by a numerical example in which the i ssue of investment time is dealt with.