Abstract: This thesis empirically studies the investment behavior of 43 firms in Taiwan’s Steel Industry.Using penal data collected from firms’ s financial statements covering the period between 2008 and 2017 to estimate the econometric model popularly adopted by economists in relevant studies attempting to find the factors that have affected their investment decision makings. Important findings are as follows: 1.The two factors, cash flows and newly created debt played significant roles in affecting business investment decisions while thepositive influences are matching the predictions of the theories. 2.In the most recent three years the favorable movements in cash flow and financial leverage has generated favorable results in business investment while adverse movement in newly created debts has dragged down investment significantly. Finally, Tobin’s q does not affect investment decisions significantly showing that performances in the stock market have no effects on firms’ investments.