Abstract: Marine oil drilling platforms is an important investigation instrument in the exploration and exploitation for offshore oil and gas, whose safe berth and steady production has a close relationship to engineering geological condition of sea floor of well field. Evaluating technique of the engineering geological condition which relates to drilling platform safety has been studied in this paper. For instance, evaluating and forecasting a weaker soil layer in its punched-through or bearing capacity that relates to the safety of self-elevating offshore drilling platforms; evaluating and forecasting the stability of engineering geology layer on the slope of sea floor conditions; evaluating and forecasting anchor hold strength of semi- submersible drilling platforms; evaluating and forecasting the different conditions of sea bed which was eroded by ocean current. An available semi-empirical formula was recommended in order to supply a stable judgment of engineering geological condition for marine oil drilling platforms.