The invention relates to a method for obtaining safe injecting-blowing strength of molten iron pre-treatment injecting-blowing gas, and the method comprises the following steps of: obtaining a molteniron tank condition, an injecting-blowing condition and a medium condition; obtaining flow Qv of gas which needs to inject and blow into a metal molten pool according to the medium condition; obtaining current injecting-blowing strength I according to a formula I=Qv/W, wherein W is charge weight of molten iron; obtaining maximal lifting height HW, max of the molten pool liquid surface near the tank wall of the molten iron tank, and maximal lifting height HL, max of the molten pool liquid surface near the outer wall of a spray gun according to the molten iron tank condition, the injecting-blowing condition and the medium condition; and judging whether molten iron splash or overflow risk is caused or not according to HW, max and HL, max, regulating the injecting-blowing condition and/or themedium condition if the molten iron splash or overflow risk is caused, and sequentially performing follow-up steps until the molten iron splash or overflow risk is eliminated, thereby obtaining the injecting-blowing strength I at the moment as safe injecting-blowing strength. The method can feed back influences caused by changes of various working conditions in real time, and remarkably reduces the cost caused by the conventional continuous trial errors.