This paperwork evaluates the impacts of external financing on market risk for the listed firms in the Viet nam construction industry, esp. during and after the financial crisis 2009-2011. First of all, by using quantitative and analytical methods to estimate asset and equity beta of total 104 listed companies in Viet Nam construction industry with a proper traditional model, we found out that the beta values, in general, for many institutions are acceptable. Second, under 3 different scenarios of changing leverage (in 2011 financial reports, 30% up and 20% down), we recognized that the risk level, measured by equity and asset beta mean, decreases when leverage increases to 30% but increases more if leverage decreases down to 20%. Third, by changing leverage in 3 scenarios, we recognized the dispersion of risk level, measured by equity beta var, increases from 0,301 to 0,408 if the leverage increases to 30% whereas decreases to 0,252 if leverage decreases to 20%. But the dispersion measured by asset beta var decreases to 0,078 (leverage down 20%), showing leverage impact. Finally, this paper provides some outcomes that could provide companies and government more evidence in establishing their policies in governance.